CENTRAL VACUUM stuff.
I'm a Central vac user who sold my Rainbows in the conversion. I have a LOT of opinions on Central vacuums, and I'll share the things I think are most essential.
I prefer motor/power units that are ALL about the power/air watts, and have essentially one function... SUCK. Any power unit with fancy digital control panels, and "luxurious" electronic controls are NOT welcome here.
I insist on having a STANDARD style/size inlet, so I can use whatever kind of hose I want.... and I want a STANDARD style hose so I can fit whatever tools I want on it.
I'd vent it outside and skip the HEPA filtration.
I find the BOTTOM mounted dirt pails annoying. I had a bagged unit, and putting the dirt pail back on was a pain... Now that I switched to a top-loader, it's 100% easier.
I'd rather just throw out a full dirt bag than have to mess with any sort of bagless system.
It's my opinion that the air plumbing should be done much like water plumbing... with the "rolls down hill" mentality in play. This helps prevent clogs, and you aren't fighting against gravity, allowing you to suck up heavier debris. In our computer shop, there's lots of screws and stuff that get sucked up, and I want them to end up in the tank and not fluttering in the hose.
The tools for a CV are amazing, allowing you to clean high and low... and with the standard tool size, you have tons of options.
My favorite power units are the ones from Lindsay Mfg... showing up as brands like VacuMaid, Imperiium, & Valet. They meet all the things I like and don't like.. the power units are simple, powerful, and reliable.
Sorry if this is too much, but once someone said Central Vacuum, it flipped my mental switch.