Bill, Welcome back to the network! Glad to hear you will be looking at controlling again as well. ARTCC selection is really a personal thing since you will want to find a facility that makes you comfortable in addition to providing you with the training availability you are looking for. Of course, that being said, sometimes it is worth joining one ARTCC to satisfy your training needs and later look at transferring to the facility where you really want to be. The biggest problem with this philosophy, in my opinion, is that people often lose momentum when they are somewhere they don't enjoy being so apply that mindset with good judgment.
If you are looking to help increase the staffing level of an ARTCC in need and are trying to avoid bias you could visit the websites of the different ARTCCs and review their roster to gauge manpower levels or send an email to each of the 3 Air Traffic Directors and inquire about their respective airspace needs. They are VATUSA7, 8, or 9 at vatusa.net for the Northwest, Southern and Northeastern ATD. This may also help you find that perfect spot in an area of the country you prefer to be in.
Software has changed and all the options could be explained after finding a new home. Again, welcome back and good luck.