Undergravel filters???

Hi there, I don't want to start any wars, but I would really like to 
hear good arguments for and against undergravel filtration in the 
planted tank. 
I have a well planted 30 gal tank with a couple of small tetras, a 
pl*co, 4 otto cats, and some shrimps.  I have been reading a fair bit 
about filtration, and plants.  I understand that having a slow flow of 
water through the gravel is a good thing because it provides nutrients 
to the roots of the plants (if the roots are even used for nutrient 
uptake in aquatic plants ???).  I have been using an "over the back of 
the tank" filter for mechanical filtration since I started up the tank, 
and an UGF for biological filtration as well. I have good plant growth, 
and the canister filter really doesn't get that dirty. The only problem 
I've had recently is a bad algae go about, but I think I've licked that 
one (knock on wood) :)

Ant way, aside from my rambling, would my tank suffer if I removed the 
canister filter?  Why? I would appreciate any comments, either to the 
list, or by private email (aph at globalserve_net).  TIA.

Adrian Hydon