Some things you should consider when choosing a pump -
How does it work with your lifestyle?
Is it easy to program?
Can you set up multiple programs for say sick days, exercise, very active days and lay about days.
How about temporary basal rates for those hormone jag days or when you are testing a new basal or bolus rate.
How much insulin fits in the cartridge- how many days will you get before you need to change it out.
What infusion sets can You use with it and how much do they cost?
How small of a basal rate can it deliver? How large of a basal can it deliver? How big of a bolus can it deliver.
Do you want microdelivey to avoid potential inadvertent ODs? Even if it meant it takes longer to deliver a dose.
Does a rapid delivery of either basal or bolus make a difference in your numbers, or does a slower more frequent delivery give you better control.
What about extended boluses/square waves- how are they done; Will it fit how you eat?
How does the bolus calculator work? Does it subtract if your below target or do you need to do it manually?
How easy is it to bolus without looking- especially useful if you keep it in pocket/bra/waistband etc.
Do you want remote meter input/control? Do you want an integrated CGM, or do you prefer a CGM that is seperate.
Do you want to rapid bolus in carbs or units? Do you want to enter a BG and get a correction.
Do you need a food/carb database in your pump or do you know/use online sites for your carb counting decisions?
Lots of things to think about, each pump has its strengths and its weaknesses. How it fits it your personal D life will help you with the decision on which pump to choose.