For the money involved in moving up, I would strongly consider either a JD 3x20 series, or a Kubota with a three range hydro if you are not happy with low range in yours.
I have seriously looked at the 3320, but rejected it for a couple of reasons:
1. Cost. The cost of the tractor, loader, backhoe and mower deck is quite a bit more than going the 2720 route.
2. Size. While I have quite a few landscaping projects that I need to accomplish, my primary use for the tractor is mowing and plowing snow. The size of the 2320 seems just about right to me, and I worry that a heavier tractor will be hard on my lawn.
The 2320 has served me well, I just would like a little more oomph.