Welcome to tpunk!
I was only in San Jose for one night and I wasn't the biggest fan. Might have something to do with an uber long travel day + border crossing, a stolen bag incident (thankfully not mine) and just the drastic change from Nicaragua - coming in to see so many spring-breaker types was just not what I wanted.
That said, I did have fun in Costa Rica, although it was more expensive than all the other Central American countries I visited. I headed to Monte Verde and also Parque Nacional Chirippo (cloud forest and hiking and ziplines, and mountains), as well as Manuel Antonio/Quepos - for jungle, animal-watching, beach and surf. I've heard Puerto Viejo is fun, although I didn't make it there...and Panama is an easy hop away from there - I've heard more good things about Bocas Del Toro just across the border.