The ability to program more than one basal rate: for example, a rate for work days, a rate for days off, a rate for working the night shift.
The ability to set a temporary basal rate: for example, you can tell your pump to give you less insulin while you go for a jog.
Several meal bolus options. (A bolus is an extra amount of insulin.)
Basic safety features such as alarms and locks.
The ability to "remember" how much insulin you have used for both your basal rate and your meal boluses.
Insulin companies also offer other features. Some will matter to you more than others. It depends on your lifestyle. Questions you may want to ask include:
How the pump works
How much insulin does the pump hold?
Is the pump's "maximum bolus" big enough for your needs?
If the pump uses an infusion set, will you be able to use different brands of infusion sets? Or will you have to use the infusion sets made by the pump company? At least one company sells a pump that does not use tubing.
Does the pump use batteries that are easy to buy?
Is the software that comes with the pump easy to use? Do you want to program your pump using your home computer? Or do you want to create your own database of how much carbohydrate your foods contain?
Does the pump come with a remote control so that you can give yourself a bolus without touching the pump?
Does the pump include a meal bolus calculator?
Are there extra alarms you can set to wake you up or remind you to test your blood sugar?
Is there a lock-out feature so that your child can't play with the buttons?
Is it water-resistant or waterproof?
Will the pump company file your insurance claim for you?
Will the pump company upgrade your pump at a discount when newer technology is available?
Can you purchase prefilled insulin cartridges for your pump? Some people find this easier than filling their own cartridges and trying to keep air out of the tube.