Mags suck. Unless you have a money tree. Look at the efficiency rating on them. They suck ridiculous amounts of power for the water they pump. They do however work well doubling as heaters. Not a good thing in the summer.
Any submersible pump could potentially have stray voltage problems. If your water is hard you'll need to descale them several times a year. I couldn't run the Pondmaster 4700 submersible I had for more then 4-5 months before it would lock up do to deposits on the impeller.
Most ray keepers would agree that more turnover is better. I just did a 180 for a buddy and we used a Dart on it and seems to work well. BUT, I had to knock a pair of holes in it for (2) 2" bulkhead fittings for drains. IF you're capable of drilling drain holes you can use however big of pump you want, BUT if what you have is what you're going to run and can't modify then those drain holes are going to dictate how big of pump you can run, unless you're going to reroute return water through a bio tower or something of that nature.
I run a small fleet of Reeflo Darts and Dolphin 3Ks. Hard to beat the efficiency vs cost vs reliability.
Look at wattage rating on Korilias and it's easy to see why so many people love them.
I'd personally run a simple sump with a reactor/UV loop off it, but it may take a little work, research, and DIY skills to go this route.