I haven't seen the 5ed, but I've been reading the 6th ed. The stats all seem to be very recent in the 5th. I bought it from Galen Press in May. I'm starting M1 this August. I figure if it gives me any decent info it's worth the $40. There's so much hear-say, BS, etc. in school that it's nice to have a book to turn to for info. Having said this I've heard people dog Iserson for various assundry things. For instance, it's been said that he pumps up EM's competitiveness. That may be true, I don't know. If you get it, read it with a grain of salt and use it as a springboard resource (he points you in the direction of several URL's, addresses, etc. for more info) -- that's how I'm using it.
Good times.