I actually no longer have the Nero -- it broke and I replaced it w/an MP10! Both are great for the Max Nano IMO. The MP10 is nice b/c of the external cord and there are more settings. The Nero 3 wins design-wise for me -- it's got an incredibly nice thin profile, and the design looks great/like less of an eyesore in the tank. But it died w/in a year. I was glad it died while I was around and I could address it right away, and in the end decided I didn't feel 100% comfortable relying on it, so I upgraded to the MP10.
I would honestly recommend either, w/the caveat that I did experience the issues others have been complaining about w/the Nero, and it happened just before the 1 year mark. If it happens before the warranty is up, the company will step up and take care of it -- you just have to send the broken one to them. As for the MP10, I am not a huge fan of the Mobius app, and had some troubles getting my program set up in it, but eventually was able to and have had no issues since.