Depends which country you are in. I'd say overall that Grappling magazine (US) is the best but there are others. In the UK there are two to choose from 'Fighters Only' edited by Ian Freeman is a high quality magazine dedicated to MMA and which covers Europe and 'Fighters' which covers MMA, BJJ, Muay Thai, Kickboxing etc. That one is nowhere near as good.
I get Grappling but I hate it. It is the best of the worst in the US. Fightsport was okay, and FCF is so-so. I would say Gracie or Tatame, it will cost you more but they are much better.
They are hard as hell to find in my area. I have a link to them on my web site. The graphic is screwed but the link works. www.SSFgear.com
The only thing I can get in ND is Grappling. It's starting to suck and get REALLY REPETITIVE. They're trying to reach out to noobs too much. Any issue between June 2001 and Early 2004 are very nice & well written. The newer ones are useless news and pieces written by complete retards. That reminds me, September issue came out today. About to leave to pick that & Black Belt up.
Gong Grapple is the best Grappling Magazine on the Planet! I highly recomend it! http://www.budovideos.com/shop/customer/product.php?productid=21494&cat=&page=1