Given the specific Chapter Tactics of Raven Guard, Scouts aren't gaining anything from their tactic, assuming you give them cloaks. Since they're mostly objective holders, that's usually a good idea. With Raven Guard, I think you'd get more bang for your buck out of Tacticals scouting around in Razors / Rhinos. Razors, in particular, could benefit from a single "big move" that doesn't limit their follow-up firepower. Consider it an 18" move that you can still shoot after on the first turn. If you're rocking the LC / TL PG option, you'll probably be in rapid fire range...
The Assault Squads would gain greater benefit from having those scouted vehicles block LOS for them, rather than Scouts just... well... doing what scouts do.
Personally I think the best use of Scouts is with Iron Hands, as objective campers. Since they tend to get the most benefit out of their Techies, you can take a couple to boost a couple of ruins' cover saves. Place a unit in each, with a Dread to babysit them. The Scouts, with cloaks, rock a TEQ cover save, with FNP junior thrown on for good measure.
No need to go to ground, even. Give them Sniper Rifles and give the Dread a TL AC or some such. Your Dread gets an MEQ cover save, and regenerates. They're pretty damned tough, and you even have a bit of assault resistance with the Dread kicking around. I probably wouldn't use them any other way, in an MEQ list. Not to say that other chapters can't use them that way, but Iron Hands happen to have the best mix of Tactics, abilities and units to take advantage of them.