i use it and love it, i would not use anything else. Priming is also very easy if you do it right, their are vidoes on youtube that will show you the easiest way of doing it.
true the flow is not as strong as comparable canisters, though this is because with the eheim classic their is 0 bypass, meaning 100% of the water that goes through it gets filtered, unlike other canisters that will allow some water to bypass the filter media to keep up that high flow.
id also recommend getting some silicone lubricant, so you can lube the O-ring everytime you have to take the top off to ensure you have a 100% seal, and o-ring will last you for years (should be done on all canisters regardless of brand that use an o-ring). dont use vaseline, that will wear down the o-ring faster in the long run.
any other questions just let me know!