newbie here ISO tahoe or yukon...

hey guys im in search of a 2002 - 2005 tahoe or yukon but dont know anything about them at all.. ive alwasy been in the import scene... but now im falling for the tahoes and yukons... wow they are hot..
whats better the tahoe or the yukon? which one holds better value?...
i heard there are sle model and slt model? what is all that?...
can someone please help me?... and if i find a AWD can it be lowered? i live in virginia so i can get slammed due to snow season .... thanks guys...