Just got this bit of news over the wire. Forgeworld has just released their updated rules for 6th Edition Marines. You've got a comprehensive Chapter tactics sheet for all of the chapters FW has focused on in their books, and a retooling of just about every Marine character they've had.
I've only skimmed them so far, but my initial gut response is "Wow."
The characters are neat, but Bray'arth Ashmantle stands out as really good. You better bring some lascannons to down that bad boy. Of course, he's a Salamander, which means his weapons are short ranged and he's slow as molasses. He'll be slogging across the table. You're probably thinking "drop pod!" but to play spoiler: he can't take one.
The best part are the Chapter Tactics though. There are some really interesting ones, like the Fire Hawks who get +1S on flame weapons when they arrive from Deepstrike, and +1S to HoW hits. Raptors, who get the option to change their bolters and bolt pistols to Heavy 1, Rending if they don't move. All of the Tactics have a reason, and fit the chapter's background.
Of course, every one of the new Characters and Tactics can be run using the standard Marine codex, which enters into that "is it Ok to run X as Y?" conundrum. Knight-Captain Elam Courbray is a jump pack Captain of the Fire Hawks, and provides some seriously cool rules (and the Fire Hawks' Chapter tactics). But should you run him under those rules while the model is painted as an Ultramarine? It's the same problem I ran into regarding White Scars, but adds the extra element of Forgeworld rules. Is it different to run counts-as using Forgeworld rules than to run counts-as within your core codex?
It's something to think about, and also an opportunity to paint something other than blue...