The good news is I upgraded my iPad to iOS 5 recently which was free but comes with a price. The upgrade itself will take about an hour and may delete some of your downloaded applications if you are not careful. We recommend that you sync the iPad apps with a Mac or PC first before doing the operating system upgrade. The upgrade comes with a lot of new bells and whistles but the most notable feature is the new Safari tabbed browser which is nice instead of flipping between open pages.
I am still a believer in the iPad WiFi or iPad 2 WiFi only versions because I mostly use the iPad at home or in the office. The costs simply do not make sense at this time when carriers have tiered data plans and caps. Compare data plan pricing here. When I need to use the iPad out and about I simply tether the iPad to my T-Mobile phone.