It's a good game but they are very quick to take your account when you're having payment issues. It's happened to me twice and they confiscated all my money with the account and basically told me too bad. SecondLife can also be extremely expensive and addictive to the point where for a lot of players it becomes a real world issue. Most of all, the people at LL are horrible and they find it easier to ban you and take your account as opposed to actually helping you with a problem. LL employees are rude and mean, whether you have a paid account or not. Also, I played SL almost since it's inception until a few months ago when they took my account...again and it's become little more than a place for real world "Escorts" to ply their trade. LL wont update the towns and cities from way back so when you travel around, a lot of SL looks old and outdated.
Last but not least, there really isn't much to do on SL anymore unless you want to go clubbing or gambling. The social aspect of SL waned over the years and there just aren't a lot few clubs and groups to be part of that aren't sexual in nature. That gets really old really quick.
If another game ever comes along that is comparable to SL with more of the focus being on the game itself, SL wont stand a chance. Long time players became disenchanted with the cost and horrible treatment by LL and many of them just dropped the game entirely.