I've been a member of Massage Envy for about a year and I am overall very pleased with the membership.My massages for the most part are excellent - I've only had one therapist that I would not go back to again.
I used to be pretty hard on my body - stilettos, cycling, running, yoga, every day wear and tear - and this monthly relief really helped not only with stress but with keeping my muscles loose and working out all the tight spots.
If you haven't done the introductory special - I say go for it! Make sure you talk to your therapist - communication on your part helps for a better massage from them - or at least, it should.
The membership plan is great if you can swing the monthly payment and you can use your massages all over the country. If you miss a month, they roll over and you have additional massages to use.
I recommend this place - I am definitely a fan of the membership package and of being pampered. I go to the same location and it's nice - the front desk staff know me when I arrive, I have two or three favorite therapists so they know me fairly well. I think consistancy is the key with any good service - if you find a therapist you like, stick to them, it will make your experience all the better.
Definitely a good way to decompress!