both seem like good games, but I'm a little hesitant on both because I've heard in morrowind you have to walk EVERYWHERE and you can't join every single guild
and oblivion just looks bland and boring from what I've seen in LPs
theres many forms of fast travel in morrowind
silt striders (big animals you ride), boats, and mage's guild teleports. as well as mark & recall (mark a spot, then teleport to it at any time) and divine/almsivi intervention (takes you to nearest imperial shrine/dunmer temple) spells. oh and this weird teleportation network or something using these dunmer fortresses, i never did that so i dont know much about it.
as far as not being able to join every guild, you just can't join any more than one of the three "houses", which is perfectly logical - there sort of like political parties now, you can't be a democrat and a republican. the houses have very conflicting views on many issues, it would be bizarre if you could be a member of any more than one.