Using Google Groups for user group mailing lists?

Atlanta PHP recently migrated to Google Groups (from our own hosted Mailman instance) for our mailing lists. I also found out that DC PHP recently moved to Google Groups, as well, and Hans (of NYPHP) mentioned to me that other groups have done the same and was wondering about the rationale for the moves. What do you use for your mailing lists? Why? If you've moved your lists to something like Google Groups, why did you do so, and what did you move away from? -- Ben Ramsey Atlanta PHP atlantaphp.org