Only issue I have is the maxis pull so hard that it creates a vortex if it is too close to the top of the water.
If you have the maxijet already, I would do the modded MJ. I have both - 2 modded 1200's and a modded K4. The MJ takes up less physical space. As for looks, I like the MJ better as well. Some of the DIY'er ones did not look that nice but the ones out now are nice.
I have one of the modded MJ's go off at night and back on in the morning with just a regular light timer. The koralia kept knocking the cover off.
I am a fan of directed flow though. With a mixed reef, the koralia seemed to push water in a direction I did not want. Modded MJ seemed to have 2x the output of the Koralia too.
Both are good. Depends on what you want I guess
*180 gal Display, 100 gal basement sump, 33 gal refugium, 3x250 MH, 2x160 VHO actinics, zoos, some softies, LPS & lots of acros and other SPS.
*100 gal prop tank plumbed into main system w/ 2x96 PC lights and 1x150 MH,