I have a mac and back in the day I was able to use it for SL but honestly it is just not made for that. I bought a new acer gaming laptop for my birthday this year so that I could play the games I like again and come back to SL.
However, I hate windows and will stick with my mac for everything other than gaming. It is 5 years old and still fast and I never have issues. It runs like when I bought it. So for work school and general stuff I use my macbook and for second life, sims, planet zoo and eve online I use the acer.