I think it's good if a lot of people experiment with different types of kernels. This can give insight into which configurations work well on Dingoo and which do not.
For the users however, I think it is important to gather all kernel improvements in one central place. Otherwise, they will have to choose for example whether to use a kernel with TV-out or one with more memory. OpenDingux was started to gather the improvements and create a kernel and rootfs that can easily be maintained. We want to stay up-to-date with new development in Linux itself, so we based OpenDingux on the kernel from Qi Hardware (the people who made the Ben NanoNote, specifically Lars-Peter Clausen who wrote most of the drivers) and are porting booboo's customizations to that. The Qi Hardware drivers are currently undergoing review and will most likely be integrated into Linus' tree (Linux mainline), maybe as soon as version 2.6.36.
There are different opinions about whether it is better to stay up-to-date or to pick one version and stick to that. booboo was in the latter camp, intending to stay on version 2.6.24 forever. OpenDingux wants to keep up with new Linux releases; currently we are at 2.6.34 which is the latest stable release. So far this worked out well, since it was relatively easy to integrate zram to compress data that is swapped out in RAM. This is faster than swapping to SD card and there are no (real or imagined) risks of exhausting the writes of the card, but it gives less extra memory since the compressed data still takes up some space. Also, the OpenDingux kernel does not seem to suffer from the SD corruption issues that booboo's kernel has, although we still need someone to thoroughly test it to make sure.
If we can get more volunteers we can progress faster. So Menelkir or anyone else is welcome to join us. We usually hang out on #dingoonity on freenode IRC.