The best way of checking how good a map is is to read it's NC review, especially those written by Matterminator (they're very insightful and usually cut straight to the point)
In no particular order I'd reccomend Rage][ Blood inferno (100% from headshot!), Scimitar (THE defining moment in UT mapping) and Helleth (Justly famous, many good reviews from sites like lvlseek and chainsaw)
Hope you stick around, we're a wild and crazy bunch here so I'm sure we'll fit right in with the PUF gang!