definitely buy it. the game is excellent, and im hooked on it. there is a HUGE number of mini mods that tweak the game however you like it, be it better unit stats, more men per unit, better AI (that would be Darthmod), all factions unlocked, differet battle tunes, better skins, blood and smoke mods, and the list literally goes on for pages.
there are also a handful of quality full conversion mods. just go to the TWC mod page for ETW and you will find them all.

even in vanilla, the game is awesome. while the AI is still dumb, i think it far surpasses RTW and M2TW. im not sure about STW and MTW. ive never played them. ive actually lost battles in ETW, even when it was an even ratio, while in previous TW games ive always won, even if i was outnumbered by a lot.

about crashes, ive only crashed once, and it never happened again. but ive crashed a ton on the initial loading screen, but only because i had mod files that were conflicted/corrupt. they are now fixed, and i am enjoying ETW to the max.