If you want "SIMPLICITY" then get an FX6 and use that in addition to the 304B....DONE!
Sumps are kool(if that's your thing), however you have to assure there are more fail safes in place if you're NOT one to VERY closely monitor your tank and sump setup. And before anyone says it, YES cans "can" leak to, but once you have one/two up and running, usually you only pay attention to the flow coming out of the nozzle(to know when it's clogging), and service once every 3+ months. Then you watch it closely(a day or two) after it's been opened and re-closed after servicing, and that's it(as long as no issue is found).
For a sump, it's CONSTANT checking water-levels etc, unless you setup an auto top-off
I personally would never setup a sump upstairs on my hardwood floors, however in my finished concrete floor basement...maybe.
YMMV, best of luck...