There are several threads discussing the D2 vs 950. Some prefer the 950, some the D2.
I prefer the D2. Covers ground better, and just plain separates better. The 950 can mask targets if they are close together. With the D2 you don't have that problem. As far as depth, the D2 might be a little deeper but certainly not any less deep. Plus the more mineralized your ground is, the more the D2 will shine.
The only time the 950 has been back on either my MXT/P or VX3 is for testing/comparison purposes. Never hunt with it anymore.
If you are use to pinpointing with a concentric, the DD might take some getting use to. I again prefer the DD for pinpointing. I never have to use pinpoint function. Just wiggle the tip of the coil to find the mark. Easy shmeasy!