Matter of taste - I have the T34 and 8.8 td, and like them. The lowe is slowe, but I've felt it's an especially nice looking tank, and people seem to like it. I thought about the FCM, especially since I have found French tanks favorites and it has nice mobility, and people seem to like it also, but it's hard to justify, given I have Russian tier 10 mediums etc.
It's not clear how it's more enjoyable than other tanks.
Well, I would say mostly the Tier VIII premiums aren't entirely about how fun they are (though this counts). They are the best money making tanks in the game.
Out of the Tier VIII prems I have
112 - Solid armor from the upper plate and turret. Bad side armor so careful sidescraping, and the gun is difficult to get working until you get used to it. Decent mobility. I've felt that once I've gotten used to it, it is my most reliable money maker. If I need to make a lot of money, I'll play 10 games in this thing due to its consistency.
JT 8.8 - Best potential money maker. If it gets in the right spot, you're making over 100k easy. That said, the lack of mobility makes it frustrating and also gives you horrible games.
T34 - Great gun makes it seem like you can always do something. Also, solid turret armor and nice gun depression means it can get in a good hull down position. However, it has some problems. First, it is terrible in terms of mobility. Its hull armor is really bad also. Coupled with the poor mobility, it gets caught out a lot and killed before it can hide its hull armor. Also, it doesn't have premium MM like a lot of other Tier VIII premiums, and it fires slowly.
KV-5 - Pretty much impossible to not make money in this thing. It is a ton of fun to play on occasion, but would be frustrating to try to do a run in it (like I do in the 112) in order to try and make money. It is riddled with weak spots, slow (unless going down hill) and the gun isn't very good except against lower tiers.
Panther 8.8 - Only 5 games in it so I don't have enough experience to do a big review. Seems pretty decent, but nothing too special. The gun is pretty nice.
IS6 and Lowe both seem decent, though I don't have them. I would say, based on my experience, IS6 seems to be a better tank if you are a newer player as that armor is forgiving. Lowe seems to require a bit more skill to play effectively, but it certainly can.
FCM also seems pretty good, but looks to be the least forgiving.