Yeah, do that. If you buy them from bicyclewheels.com, have a shop tension the spokes (might even be a little out of true). The cxp-22’s I got from there definitely needed it. Spending the $30-40 after ordering them will really pay off in the long run.
This is just going to boil down to a matter of preference. Both are perfectly fine rims which will last you many miles of happy riding with minimal maintenance. Now, do you want a deep section or a box rim? If you want a box rim, get the Suns. Deep section, get the Velocitys.
I got them for the last build on my road bike and do not care for them. They seem to require constant truing. The rear developed some nasty cracking around the eyelets. Granted, I had quite a few miles on it at that point, but still not cool.