I am a member of Planet Fitness. What lured me in was the fact that it was so stinkin' cheap...as far as gyms go. Well, and the fact that when the weather is such that I don't want to run outside, I don't have to. Planet Fitness has two different options when it comes to membership. You can get the "White Card" that allows you to utilize just your gym, the one you signed up at, for only $10/mo. Then, there's the "Black Card." This type of membership allows you all sorts of extra stuff: free tanning, half off cooler drinks, free use of massage chairs (um, no thank you!), unlimited guest passes (one at a time), and use of any PF gym you care to attend. I have the Black Card since I really wanted to take advantage of most of these perks. The one I've most taken advantage of is the use of other PF gyms in the area.
Planet Fitness is a franchise gym. So, they are not all the same. Yes, they are similar and have the same branding ("judgement free zone", yellow and purple EVERYthing) but other things vary. Here's a brief assessment of a couple that I've been to:
Woburn - this is my home gym. it's small but clean, not overly crowded, friendly, only 6 channel of TV to choose from.
Wilmington - lots of entertainment choices, flat screens are close to cardio (read: you can see w/o squinting), a good amount of cardio machines, very clean, my friend is a member here.
Burlington - old building, little parking, locker room was reminiscent of one you'd find in a HS in the 80's, not very friendly.
Danvers - HUGE! lots of parking, clean, busy (even at 8pm at night), lots of young people, very nice locker room, too hot (seriously, the temp was around 75 with no air circulation...).
What I have come to conclude is that while they are all PF's gyms, they are not all the same. Some are better than others and I'm glad I joined Woburn instead of Burlington, where I considered joining... And, hey, that guest pass is always on the table if anyone wants to check out the Woburn gym. Just let me know.