Personally I found Reno far more fun than Junktown. After all of these post-apocalyptic films/shows/games we've had so many damn "junktowns" that it is getting real stale and boring to me. Junktown just feels like another rusted scraphead. Reno on the other hand, as zany as it is, is far more interesting and fun to me. So I totally get why he'd prefer Reno over Junktown.
Hell, when we get down to it a lot of places in Fallout 1 are quite lacking. Necropolis barely has anyone to talk. Shady Sands, while it has an interesting art design; It is over too quickly.
Only places (civilized places and not dungeons or shit like that) of real interest are Hub, Boneyard, Lost Hills and uh... Cathedral? Compare that to Fallout 2 where there's Klamath, Modoc, Gecko, Vault City, Broken Hills, NCR, San Francisco (I don't get why people got so many problems with this place), Reno, The Den and Redding.
Not only does it have 'more' locations, each of the locations also has more content to them and feel worthwhile to explore and none of them feels like they lack content.
I still prefer Fallout 1 over Fallout 2 as a cohesive whole as Fallout 2 is a bloated mess but Fallout 1 is quite lacking in some areas which Fallout 2 is not.