What are your thoughts, which is best and why ?
I'd save up for Red metal 3's whici are tubeless. Nice wheels the Fulcrums but a mate has had problems with 5's but I've had 3's for 2+ years & they've been perfect.
I've been impressed with the Crossrides I have, they came on a new bike and I was a bit sceptical having read about split rims, spokes breaking and freewheels breaking down but maybe that was older models, these have been on a fs bike clattering up and down a trip across the Alps as well as at home, but I think both the wheelsets you mention have specific spokes, I know the Crossrides have the flat spokes but not sure about the Fulcrum, which could be difficult to get hold of. I'd save a bit more and get Pro2's if I was looking for new wheels.
I have red metal 5's, went for them over crossrides as they were a bit lighter and my brother pringled his rear crossride rather easily. I took the big silly stickers off mind. They have been fine so far (few months). They do have bladed spokes. Don't expect spares would be a problem as I found Jim Walker the UK distributer good when I needed spares for the fulcrums on my cross bike.
The freehub makes quite a loud click so if thats not your thing dont get them
I chose RM5s over Crossrides after doing some research and asking on here. My choice was also coloured by the fact that my older crossride (2007/8 I think)had ripped a spoke out at the hub (actually shearing the flange thing) while I was stopping gently at a traffic light. I swore off straightpull after that even if Mavic's warrenty department was very good and had a new wheel to me a week later.
The Fulcrums are about the same weight as Crossrides; claimed weight was off by about 90g for the pair on mine. I actually feel that they are stiffer than my old crossrides, but that might just be me. The freehub engages faster too, imo. The rims on mine have taken as much of a beating as any mavic rim I've ever owned (possibly more, as I ride more often now) and haven't had any dings of needed trueing.
The only problem I've had, in just over 6 months of riding (off-road) 4-5 days a week, is that the bearing preload collar on the rear hub needed some loctite to stay in place.
I'd definitely buy Fulcrum again.
Check german bike websites as I got mine from one of them at about £50 less than anywhere in the UK.