I have a 2320 and have the 53" bucket. For my needs, I do not want a larger bucket as I need to keep things compact in some of my tight spaces. That said, the 2320 will handle the 61" bucket. It is as stout as the 2520 or 2720 with regard to ground engagement and lifting capacity, it simply will not lift as fast secondary to the lesser hydraulic flow. In short, if the 2520 will dig it, the 2320 will too. The major issue with the 2320 is that the loader is not very fast (not as fast as the 2520 with the dedicated pumps) but it gets the job done. One thing to remember: with regard to larger buckets, box blades, etc., the extra width in many cases does not help get done that much more quickly. I have owned compacts from the 2000, 3000 and 4000 series John Deere line and have been surprised in most cases how close in speed the models are. The larger tractors really help when covering longer distances or tackling huge piles of dirt, etc., but for the average homeowner like me I have found only small differences. My 2320 will move and spread a dumptruck load of mulch within 15 minutes or so of being as fast as my 4520, and is quicker than the 4520 boxblading my drive, in no small part due to its much enchanced manuverability on my hills and steep switchbacks. I can also plow snow and such that I would not have even attempted with my 4520 (due to fear of sliding off our mountain). Now, everything has its limit and my findings are due in part to where I live, which is steep and tight in many places. A smaller, more manuverable machine excells in the this enviroment, where a bigger machine would have its lunch in more open areas. The point I am making here is that many think an 8" larger bucket will really enhance loading speed, etc., and it really doesn't unless one can utilize the larger bucket fully--all the time--which most of us do not do. I personally would go with the 53" bucket, but that is not because the 2320 will not handle a larger one; just that the slight efficiency improvement ( in some--but not all--cases) to me does not offset the reduced manuverability.
John M