I spent four months in Phnom Penh over the last year or so and overall I'd agree it's not a bad place at all. Downsides are stinky trash everywhere, pedestrian-unfriendly streets, and a generally dodgy and unsafe vibe later at night. I think if I go back to Cambodia for another extended stay I'll try Siem Riep.

Personally I prefer Vietnam but Cambodia is definitely a good option too.