Hi Bklyn Girl - if you had rectal cancer (as I did) you may be an excellent prospect for irrigation. You can irrigate if your colostomy is in the sigmoid or descending colon. You need to ask your doctor if it is right for you and DEFINITELY do your first attempt at irrigating with a WOCN (ET nurse) in an outpatient setting (or at home if you insurance will pay for it).
I use the Coloplast irrigating system because I like the thermometer on the bag to tell you the temp of the water and a little waterwheel to show you how fast the water is entering your body. (When you first irrigating you want the water to enter slowly or you might get nauseated.) You just need to get the Convatec irrigation sleeves that go with your size flange.
I use Hollister products and get the Hollister sleeves that fit my 1 and 1/4 inch flange. I can't recomment their irrigation bad though - it's too small and there's no regulating the water flow. I'm sorry I can't comment on the Convatec irrigating system - I haven't seen it, but I do know a 75 year woman who uses it!
There is a thread on the UOAA website about irrigating that can give you lots more info as well.
Irrigating has made all the difference for me.