Yeah, I like my nano wavebox. It even moves water between the rocks, which is the main reason I run it. I don't want any stagnant water. It makes softies and LPS look great with the back and forth motion. You can't really tell with SPS but I'm sure they appreciate the all over flow... I could give credit to better polyp extension but to be honest, I haven't paid attention to that.
I couple this with two koralias to keep my flow moving as it is suggested that the nano wavebox not be your only source of flow. It'll move everything back and forth and keeps things from settling but it still requires some type of laminar flow to blow everything away.
They have great customer service too. I bought mine used from another reef and after I quieted down my return flow, I started to really hear the nano wavebox. I figured something was wrong so I emailed customer support and he said to just drop on by (luckily the only Tunze distribution office in the whole US is 5 mins from my place) and he'll make sure there are the rubber 3m nipples on it to isolate on the glass (which they weren't there) and take it apart for me and take a look inside. That's amazing customer service, they really back what they sell.
+1 on the nano wavebox, though I am biased as I have never had an MP-40.
I wouldn't worry about the lack of flow, just don't leave it that way for like 4hrs! I usually just push my feed timer on the nano wavebox controller and presto, I have some time to do my water change without it sucking in air and blowing bubbles all over my tank because the water level is low. I do leave my two koralias on during the water change though.