TBH it doesn’t make a massive difference if you choose say hope hubs and mavic rims or shimano hubs and stans rims or any combo of the above. You’d probably even be able to get some end of production factory wheels at that price, I think you you can still get Easton havens for under £400 squids.
Choose what’s important in a list, is it serviceability, or weight, what would you compromise on?
If it was my money, I’d build some stans on shimano hubs* bit on the faffy side to build as you have to be careful with tension but Tubless is less of a faff, and they are bullet proof, and they’re a bit lighter than mavic.
* some people will tell you that cartridge hubs are less of a faff to service, but shimano hubs are relentless if you look after them from the get go