Once pumped, is the pump easy to disconnect from the inner tube valve?
I currently have a pump which is very hard to disconnect after pumping and it is ripping my inner tubes apart when i have to yank it off once its pumped. Plus it means my hand flies into the spokes which are bladed and this is not a pain free experience.
Have had a Joe Blow stirup pump for about 18 months without ever having the problem you describe .... and I've had a fair few punctures in that time!
Hope that's helpful - in gen my experience is it's a good solid pump replacing one that was frankly cheap rubbish. I've no regrets on my purchase and would buy another