Very Nice.
I think it will be a touch better than them combined. The Boom and + IIRC are each 30 watt speakers. This will be 80 watts (2x30 watt woofers and 2x10 watt tweeters). I also like it has a 3.5mm auxiliary jack (improvement over the Boom). I have almost 7000 Flac and Hi-Rez files.
To me the 1 downside is it is Partycast instead of TWS (that only comes into play if you have 2). If I acquire 2 I’ve already came up with a workaround. I have wired headphones that terminate into a 3.5mm connector that plugs into your source (smartphone, etc) and has 2-3.5 mm connectors that plug into the left and right ear-cup. So it I used that cable plugged into a source, then 1 into each of the Boom+'s, they would be in essence TWS. Just thinking ahead.