Speaking from experience since I live in the area and I have clients who have lived in both gated community - I like the location of enclave better. You are pretty much one block from White Rock lake and it attracts a lot more biker and runner to live there and within the community there is a creek and a big trail along the creek. I just love that!
And Stonegate is a little further East of the White Rock Lake area and the home seems to be newer but you are somewhat next to businesses once you got out of the gated area. But it is still are very charming area once you got into the front gate.
These are both pretty similar communities. If I remember right Enclave might be a little older on average and have some smaller homes than Stonegate, so if price is an issue, you may be able to get a lower price in Enclave.
Both have good locations if you like the White Rock and East Dallas area. They are close to downtown if you'll work there. They're both one of the new communities in this area, where there are many more older and established neighborhoods.