Hi Hazey
Both high and low bgs are perfectly possible for pumpers.
Some (but not all) pumps come with an in-built or associated CGM (continuous glucose monitor) which measures the glucose levels in interstitial fluid (lagging about 10-15 mins behind blood levels). However these only tell you your level, there is no automation in insulin delivery... yet.
I wrote about my own (confused and still slightly pump-averse) feelings here:
My pump problem and CGMS envy. There's a link on that page to an account by
Shoot Up or Put Up's Alison which is an incredibly convincing case for pumps and well worth a read if you looking into the idea.
I think what you are talking about is more of a closed-loop/artificial pancreas system which is still a few years away.