I have used ComponentOne and Infragistics and some other smaller widget kits and I have a warning:
All of these big vendors produce highly over-featured over-complex controls with large and dense documentation that wastes a lot of time unless you have enough staff to assign someone to become a guru and study and experiment. All of the controls will work out of the box in vanilla mode, but once you start to push them hard your learning curve will steepen and you'll be bogged down in quirks. The dependencies on licence files, versions and compatibility might really complicate your release procedures. Once you get into these kits you might as well consider yourself married to them. Greg
