The Optimus also comes stock with OS v.2.2.1. Multitouch, Adreno 200 GPU, everything about the Optimus is much better than the Ascend. 3.5mm headphone jack (opposed to 2.5 on the Ascend). Proximity sensor, which makes an end call button unnecessary. The menu, home, back and search hardware buttons are all that one would need. The best thing about the ascend call button, was being able to answer the phone because the slider would always freeze. The search button is also very very useful, giving you a search shortcut in a lot of different apps and the browser. The only thing the Ascend has on the Optimus C is support. I can tell there aren't very many people that have this model, and there doesn't seem to be anyone developing or trying to root. But, development isn't totally necessary, this phone rocks!
EDIT: The Cricket website says the Ascend weighs less, but that's definitely untrue. I have held both in opposite hands at the same time, and the Ascend is definitely heavier.