I've stayed at the Homewood and the Hampton.
The Homewood is nicer with a great evening reception. Note that they don't have bathtubs in the studio rooms (I've never encountered this before). They were nice about it and upgraded me to a one-bedroom suite.
The Hampton is fine and usually a lot cheaper. The only problem I had there was that the manager told me they knew nothing about Gold benefits! When I returned I wrote to Hilton and they gave me bonus points along with a copy of a letter to the hotel about elite benefits.
There is also a Hilton Garden Inn next to the Homewood, but everytime I'm in Champaign it's either very high priced ($189?) or sold out.
All three hotels are within walking distance to restaurants with the Homewood/HGI in an area with more options.
Marcia