I remember not connecting well with the pilot when I viewed the cross-over episode, while mildly enjoyable I didn't feel the connection to the characters like I did with NCIS. However only recently have a started watching from season 2 and I have loved the changes they have made to the show. The introduction of Deeks and Nell, and pushing Nate back into a recurring role has revitalised the show and given it some new dynamics (as well as replacing that lead woman with Linda Hunt).
The show is fast paced and adrenaline inducing, there are great chemistry's between the lead's from the bromance of Callen and Sam, to the sparks that constantly fly between Kensi and Deeks. Personally I find Eric a little flat, but Nell is always peppy and entertaining. Of course Hetty is the glue that holds the team together, and her relationship with the team and Callen particularly, is always great to watch.
While I watch both NCIS and NCIS: LA I wouldn't be able to comfortably compare the shows, it feels like they come from different worlds, LA has the explosions, constant under-cover work and wildly extreme cases. From my recent viewings I'm actually surprised to be finding the LA counterpart more amusing than the recent seasons of the original.
Overall, I would definitely suggest you give this show a chance, skip most of the first season, highlight episodes start from 1x15 'The bank job' and continue forward as Deeks is introduced, from there it only gets better. Stand out second season finale and first episode of the third season, with many brilliant stand alone episodes.
I look forward to watching this team grow over the (hopefully) many seasons to come!