I started out with the Blue Spirit pump, and 17 months ago I had it upgrade to the newer Combo, I didn't get a choice about what pump I had, it was a case it's this or nothing! But I must admit I've got no complaints and I do like my Combo, having a the combined remote/BG meter is something I would really miss now...
Choosing your first pump is difficult, because your not 100% sure what your actual needs are within insulin delivery, such as for one a increment of 0.05 in the basal is fine, but for another they may need the advantage of having a pump that can deliver a 0.025 increment!
But main factors, is checking out the menu side of things, is it easy to navigate, can you see the screen clearly! How many profiles does it have, and how many times in 24 hours can you adjust the basal rates, with the Combo you can adjust it every hour, but with a Animas 2020 if I remember rightly is was 8 times but you could program the start time and finish time of each segment.. But even with this for me it would cause problems as my basal changes 13 times in a 24 hour period..
Back to profiles, the more the better, as when I first had my pump, I need all the 5 profiles, due to shift working, and I also when making adjustments to any of the profiles, keep a back of my the profile I started with, so that if I make several different changes over a couple of days and waters start getting really muddy, I have my original starting point..