I have both the 50mm uld and 65mm m-la. Both are quite sharp, shaper than the 110mm f2.8 I would wager. The 65mm is probably slightly crisper, but it doesn't matter if you don't use a cable release, for instance. The 50mm is also a great near-macro lens. Both exhibit noticeably distortion compared with large format lenses.
Those prices sound a bit high to me and I bet you can do a little better. I kind of want to sell these lenses but I can't bring myself to until I convince myself I can achieve the same quality consistently with large format!
The 50mm uld seems overpriced simply because all well-corrected ultra-wides are (it's no better than the 65mm; just wider) but I would go for the m-la over the regular 65mm just because this is like the sharpest lens on the system and not that much more expensive.