I use Bite for my mobile phone service here in Latvia. The service has been just fine. The call quality has been good and coverage has been adequate all over Latvia. The price is excellent. For 2 lines with 500MB of data my bill is usually around 9 Lvl per month.
The customer service representatives are polite and helpful. But if the issue is more technical in nature then it might take a while to find the right person.
As far as phones are concerned. My recommendation with all mobile phone operators is to purchase your own unlocked phone privately and then purchase a SIM card and service from the operator. This will save you hundreds over the course of the life of the phone and help you avoid any cancellation charges should you decide to change operators. Prices for mobile phones in Latvia are very high and even make prices in the UK look cheap. I usually purchase my phones on eBay and have never had a problem with one as long as I buy it new from a reputable seller.
Riga Ratings 