EZ Pure vs RO/DI Cart

When is one a better choice than the other?

The filtration is the same between the Ez Pure and the R4. The cart however comes w/ either a 110v motor or 12v battery and pump mounted on a frame for easy transport. The carts (R3 and R4) can run multiple poles and the EZ Pure runs one.
The EZ Pure says it can be used up to 4 floors w/ no pump depending on the tap pressure for one pole. And the others will run multiple poles up the same height. So the real question is in your business what do you need to accomplish?

So for some guys the EZ Pure would be best. Buying a cart would be wasting money. Other guys need a cart.

One guy doing houses with good faucet pressure should get an EZ Pure, right?

Are the filters more expensive on one than the other?

All the filters on the RHG (Ettore) line are the same. I would say one one guy working in an area w/ decent tap pressure would not need anything over the EZ Pure.
It would probably be a good fit for you Mike. Ettore Caddy System