For simplicity I'm going to call it the Battlefront (BF) model rather than Battlefront\GaleForce9 as otherwise my fingers will fall off, and Plastic Soldier Company (PSC) for a comparison.
The expansion itself is a rather large blister pack containing two sprues to allow you to build either a JagdPanther or a Panther.
You also get the relevant Tanks game cards for both and a hero commander card that is not available in the starter set, plus a couple of duplicate cards you already got in the starter but are useful anyway. Lastly there is a short assembly guide printed on the back of the full colour insert \ cover, showing a Panther Ausf A in Zimmerit anti magnetic paste - which is rather naughty as the model is actually an Ausf G and has no Zimmerit. In fact the image is a retread of the box art of BFs Panther Ausf A platoon - which is something I may come back to later.
Cost is somewhere between £5.50 and £7.00 depending on your source. For comparison a single Panther from PSC is £5.50 or four for £20.00 but of course you don't get the Tanks game cards.
The two sprues are interesting - both models share the same lower hull and running gear so you can only build one model and will have a pile of spare bits. If you were rather resourceful you could have a go with magnets or similar and have the upper hulls interchangeable if that's your thing. or you could build the Jagdpanther and use the spare turrets as emplacements - or you could bin them :-)
The other thing that initially puzzled me was that there was a lot of "spare" bits on one half of the sprue that were totally extraneous - extra ball mounted hull MGs, a spare cupola, different exhausts etc. None of these were needed and the cupola wouldn't fit the turret anyway as it already has one. So what were they for? Then it hit me. The sprue was actually a conglomeration of an older sprue that had been designed to be packaged with the resin models to replace at least some of the metal bits, and at a later date a new sprue has been added to replace the resin bits. They have probably included it because it contained some bits of stowage - spare wheels and tracks etc. I'm not sure what this says about the company and their design capability in that rather than including these in one sprue when at the design stage they decided to shunt the two together??? Given the number of bits on the extra sprue that are actually useful is rather small this seems a particularly wasteful approach. Why could they not get it all on one sprue? I suspect this has a lot to do with BF using "traditional" design rather than 3d CAD like PSC. I don't know if this is continuing with BFs more recent models or if they are \ have switched to CAD? Here's the old bit ringed in red so you can see what I mean. A close inspection shows one sprue dated 2012 and the other 2015.
Ok I can hear the exasperation building - get to the model!
So I stuck one together as a Panther. The instructions are clear and simple to follow, or rather would be if there were not so many extra and unusable parts on the sprues. The plastic is user friendly and assembly was fairly quick and pain free using side cutters to remove from the sprue, an ExActo knife to clean them up and Humbrol Liquid Poly to glue the bits together. Parts fit nicely with the possible exception of the cupola hatch but that may just have been "finger trouble" on my part. It certainly looks the part. Although there is no mention on the packaging or instructions this is pretty clearly an Ausf G looking at the glacis, turret and exhausts. There is no Zimmerit which is a shame, but other than that it seems a nice model................... except the side skirts. I stuck them on and immediately the alarm bells rang. They just don't look right. If you take a glance at any of the skirted panthers around or in wartime photos it is instantly clear the skirts usually cover the top of the road-wheels and tyres. In this model they end above the wheels clearly leaving the tracks visible. I disapprove on principle. The JagdPanther is a breeze to build and looks rather nice.
This is of course very much a rivet counter \ trackhead thing, and if you didn't have it pointed out or don't really care it is probably not an issue. If you are you could always leave the skirts off I suppose, or build a new set out of plastic card but that's a lot of faff. I checked the Plastic Soldier Company Panther out and they seem to have got theirs better (or right?). Dimensions are a bit off - the Panther is a couple on mm too long and too high but that isn't a great problem - they certainly look the part.
So is this a deal breaker? Hardly. It's a nice model, and in comparison to the PSC one has fewer parts so less to screw up - particularly the much commented on two-part PSC tracks. The BF Panther has 15 parts if you exclude the skirts and extra stowage, the PSCF one has 23 (assuming I count them correctly). Zvezda, the undisputed Kings of Quick Build 1:100 (don't mention the Katyusha) are releasing a Panther soon and I would expect based on their previous performance that will be around 10 parts or less. On the plus side only BF will allow you to build a JagdPanther or a Panther G, which is something I suppose, but PSC will give you the parts for Ausf D, A & G.
I think the comparison with Zvezda is quite interesting because Tanks is aiming at that hybrid wargame \ boardgame slot, Zvezda's Art of Tactic (AoT) game is squarely in that slot too, but unlike Tanks, AoTs models are designed from the outset as gaming pieces in a board game style rather than reusing traditional wargaming models as BF has, and it shows. Less pieces, easy to assemble (mostly) and significantly cheaper. They also originally came with the cards required to play AoT but have now moved to downloads. I think this is the nub of my concerns for Tanks. BF have always been behind the trend as far as plastics have been concerned. They are improving rapidly, but most of their product is still tied to traditional hand made masters with the models cast in resin and metal (or plastic). At the same time PSC are ahead of the game with 3d CAD design and all plastic kits from the outset. That suggests BF lack the flexibility and footwork to release anything new for Tanks very soon as they have already exhausted the available models in the initial release and announced follow up. Games such as X-Wing, which Tanks openly admits to trying to mimic, have identifiable release schedules that help keep the game fresh and the punters coming back for more. I'm not sure Tanks can deliver that because it is tied into using "re-purposed" BF Flames of War models, which may suggest this is not going to be a game with long legs. Similarly reusing images from previous Bf Flames of War releases may be ok, but when the image isn't what is in the box there has to be a question asked - particularly as they have a similar but correct Ausf G image available to them.
So to sum up, the Tanks Panther expansion has quite a lot going for it, but some issues. If the comparison was simply as a model of a Panther tank PSC may well shade it, including on price. As an expansion for the Tanks game there is much to recommend in the BF model. In the end you pays your money and take your pick. As I have three of these already due to splitting starter sets and buying the expansion (yes I didn't think it through), AND my WW2 German armour collection reads PzI, PzII, PzIII, PzIV, MAUS I think I will get a few more (and leave the skirts off)
and lastly, I decided to give the whole "magnetise the hulls so I could swap them around" idea a go. I diligently made a spacer using a couple of ex GW slotta bases and stuck them in strategic places.
It worked well enough at first glance but on reflection I decided these models are going to get a lot of handling and it wouldn't take much to overstress the spacers, so I gave up and glued everything :-(