You dont say what hubs?I’ve got ex1501 on 240 hubs and they are the utter shizznit.
EX1501 is the wheelset name, all the hubs are 240s, branded as Spline 1. The rim is EX471.
I built the same last set year, and a few sets of Hope Pro4s on Stans Arch MK3.
The DT EX471 is by far a stiffer rim, whether or not that’s a good thing is up to you. It feels carbon stiff to me, very direct feeling.
The Stans rim is more forgiving, and a touch lighter.
If you’re building yourself, and you’re not experienced – then I’d go DT, as Stans rims need a careful hand with spoke tension.
With such good alu rims around, I don’t see the point of carbon anymore.