I guess it depends on how you look at the Marines. Are we talking just the plain old Vanilla marines, or taking into account Marines of all varieties?
Reasonable distinction. I'll leave it up to the poster's discretion. I have only limited experience with the "boutique" marine chapters (all them fancy-pants folks who get their own book), so I'll mostly only discuss my experience with Marines of the standard variety. Second Edition
I didn't play against a lot of marine players in 2nd Ed, but I remember them being quite nasty (if not quite Eldar nasty). Back then they were the only crowd that could double-tap bolters, Terminators took a 3+ save on 2d6
, and Master Librarians were basically teleporting unkillable badasses. In an era of wildly overpowered codexes, they were solid competitors. I'd give them a 7.Third Edition
I mostly missed 3rd Ed, but I do remember the rhino rush being unpleasant. For that alone they probably deserve a 7 or 8
, but I didn't play against them enough to get a good sense. Fourth Edition
Oh God, yeah--I remember those assault cannons everywhere
. I still did pretty well against them this edition, so I wouldn't call them overwhelming (I rocked them with Tau on a regular basis). I think a 7 does it, again. Fifth Edition
This is when I started playing marines myself. The 5th Ed Vanilla Codex was perfectly useable and fair. Assault Terminators were very strong, but I don't think we can accuse this codex of being overpowering by any means. I'd give it a 6.
The Space Wolves, though, deserve a mention here. Due to wound allocation shenanigans and the new Storm Shield, Thunderwolf Cavalry was an absolute be-atch. When you add in the fact that all the basic Wolf marines were far better than vanilla marines and cheaper, too, it started to get ridiculous. Then when you factored in cheap Razorbacks and Longclaws that could shoot all those missiles wherever you pleased, it started to get really bad. I'd give 5th Ed Wolves an 8. Sixth Edition
Marines took a hit in this edition, I feel. Grav Centurions were awesome, yeah, but there was no way to deliver them. Chapter Tactics was a really cool idea, but none of the abilities were really that good. Librarians were nice and cheap, but their powers were so-so unless you were lucky with your rolls. Rhinos stopped working very well. Speed or long range firepower became really important, and the Marines struggled with either unless you went White Scars. Still, they were okay; I'd say a 5.Seventh Edition
The addition of formations made marines much easier to use and more dangerous, too. Chapter Tactics got upgraded, the Gladius Strike Force gave them all kinds of free models, and now Grav Centurions are dropping out of drop pods. Bikes are very good, too. Much better book overall, quite flexible and pretty powerful. I'd give them a 7.