Some notes for future reader:

The EC sanders really require dust collection. Can't be used with a bag/canister or without a vac attached. Technically they can- but that's a discussion in itself.

The EC125 can have its pad swapped for the 150mm pad - giving one more versatility for $45. The ec150 WILL NOT take a 125mm pad though.

For a first sander, or low use situation the ETS125 / Pro5 is a really good choice if you're a hobbyist and looking for a finish sander only. It's not designed to flatten slabs or clean up decks like the RO sanders. Nor is it a flat panel eating racer like the EC150.

Someone mentioned the Bosch 1250devs. It's a good big sander too. Not quite a RO150; but it's probably 70-80% of it - yet costs LESS THAN HALF what a rotex does. Uses regular sandpaper you can get anywhere too! It makes a compelling value prop. unless you are well set with festool and will constantly swap tools on a plug-it , or simply want the best.