The 3.0 does/did have its issues w/head gaskets and burnt exhaust valves, both of which are easily resolved.  If you know the service history of a 3.0, and it has had a the HG recall done by a Toyota dealer, it should be an alright rig to buy.  However if you are new to mechanics, I would recommend the 22re, it is easier engine to learn on and maintain than the 3.0 is, and as mentioned cheaper to build.