I went back to 6.1.2 after trying to get 7.1 to play nice on my D1. Even with a 128 MB swap partition and V6 Supercharger script (6,8,26,28,30,32) the system bogs down after about a day and needs to be rebooted. It's even worse with compcache. The camera app is also unreliable. I have the same setup with 6.1.2 and it's smooth like butter with hardly any issues. This is with the deprimed kernel, same V6 settings, 128 MB swap partition, and a 656 MB ext3 partition with around 175 apps installed on the phone. I can't really think of any lost features other than some nicer ring and notification tones and a few extra tweaks, but I'll take stability any day. I also have better battery life with CM6.