I'm not an Inferno player, but I think some of the main inferno strengths areThe big problem for Inferno is that other than the T6&T7 the units are incredibly weak and the specialization of fire magic in the guild is an annoyance for a race with only 1 fire immune unit. The Inferno Gates cost too much to be really powerful and it requires nothing but Inferno cities so the value goes away once you reach into enemy/neutral territory.
1) Early efreets. Can get the lava lake rly early.
2) Demon raising. Sacrificing familiars only to raise demons with pit lords.
I guess it would be the most challenging town to play for a beginner.
As for the balance between towns discussion, I'd refer to WCL statistics page on http://www.heroes-iii.com/
Sure, the game is not perfectly balanced, but win:loss ratios for towns are quite close to being 50:50, so I'd say - don't bother too much with it, just play the town you personally like best.