I owned a pair of Red Power XL in 26″ variety (still have the front wheel in the garage). My experience was more or less the same as Northwind’s.
Great wheels for a cheap price while they work (if a little narrow by today’s standards). Coped well with general XC and trail riding. Problems;
1. The freehub bearings only had seals on one side, hence they got destroyed after a few wet and gritty rides. Fulcrum / iride (the distributors) wanted 70 odd quid for a whole new freehub. Managed to source some of the obscure sized bearings online but was quite difficult to change them due to a strange sized circlip which needed the purchase of a new tool.
2. The rear has a strange preload system (despite running on cartridge bearings) that I could never work out.
3. The spoke nipples are made of cheese and fall to pieces when you try to true the wheel.
4. You need to buy an expensive box of spokes if you need replacement nipples. iride wouldn’t sell me the nipples on their own. Fulcrum themselves don’t answer the phone.
5. There are 4 specific types of spokes used in the wheelset. If multiple spokes break, you need to buy full boxes of each one (potentially £100+ cost if you have a bad crash and need to replace numerous ones).