Hope IME aren’t even that reliable- I’ve had pawl spring issues, broken axles, and they go through bearings. They can be good value in a built wheel mind. DT 350 is a way better option these days imo, DT 240 is better still but also very expensive. (I have a couple of sets, mostly I’ve bought used wheels and scrapped the wheels for the hubs. EX1750s can be had for around the £100 mark. Just be careful, because the hubs last forever there’s some very very old ones out there, still working fine but not 15mm compatible)
Rims… Flow Ex was good but DT and WTB both have them beat hands down imo. I like lightbicycle carbon- I’ve had 5 rims, and they’ve all been raced and ridden extensively, trail and dh and enduro, I did manage to break one eventually but it took a long time and any number of big hits. (I notice no difference in ride quality from equivalent alu and carbon, built by the same guy). I’m not a fast racer mind but I do like to batter through rocks and roots and let the wheels and suspension do the work.
But it’s a big expense and alu rims have closed the gap a lot lately. If I was you I’d most likely go with WTB Frequency i25s- they’re not the lightest but they’re a sensible width and they’re very, very tough- I had a flow which I cracked, then a flow ex which I mangled, the Frequency is stronger but also much more dent resistant.
Proprietary parts can bugger off, as can straightpulls. You want to be able to walk into any bike shop and get spokes (OK, you won’t always get all lengths but at least you have a chance with normal J spokes) But if you must buy some stupid wheel system deal then Mavic are probably the only ones you should consider. Not because they’re great, just because you can at least get parts.