I lost my Lumia 710 to the green tinting problem, too. Finally created an account here to mention it. T-Mobile was insultingly unhelpful (the people in the stores were great, but they aren't allowed to help with hardware problems and I had to deal with horrible call center people who basically drove me away from using T-Mobile ever again). The good news is that Nokia was very polite and helpful and fixed it for me in about a week, extremely fast turnaround. I would consider buying another Nokia phone after being treated so well during a problem.
However, I sold the phone on eBay when Tmobile wouldn't unlock the phone for me despite it having been six months after I bought it outright from them and the store having told me when I bought it outright that unlocking was allowed after an initial period. I miss Windows Phone and expect to go back at some point. I don't know if the 710 has reliability troubles or if I was just unlucky. I never abused it. A friend's 710 is going strong and he admits to being a bit rough with it. Good luck 710 owners everywhere, I enjoyed having a smaller phone instead of those surfboard-type large ones.