I have spent time there a few years back when I was doing the Euro cities.
The good:
Riga itself is a superb looking place.
The women, be it indeginous Latvian or the Russian Latvian are approachable and hot.
Some cool bars and clubs.mainly 2-3 places that were any good.
The bad:
The men like to get stupid drunk and fight...a lot!
No joke, any excuse, they get hammered and fight.
I saw numerous fights throughput my stay there. Not even weekend type drunk fighting, talking mid week.
There are the typical rip off drinks type bars, so research before hand.
They, do not like foreigners, keep a real look out for any of your party if they are of colour. They are targeted.
Don't be rude, especially drunk and obnoxious it will lead to a fight.( I mean it, these people like to fight).
I saw numerous fights break out far too regularly in bars and clubs for it not to be an issue.
Like Paris, Prague etc...use your common sense and you'll have a good time.