Orks, you just gotta love them. Aside from their codexes being one of the most entertaining reads, they are just fun to play. It usually doesn't matter if you win or lose so long as you can WAAAAGH across the battlefield.
Also, conversions are just fun. You have more leeway then any other army and usually, the sloppier and ragtag the conversion, the better they look.
Alas my ork army has been put on hold. First by the daunting task of getting them all painted then by the looming prospect of a new codex. Now that the codex is here I may be investing some time back into that army.