Back in '08, IIRC, I won a free copy of Studio One Artist in a drawing at the Presonus booth at NAMM. I didn't wait until I got home but installed it on my laptop that night at the hotel. Stayed up late figuring it out, went online and watched tutorials, jotting down notes on what it got right.
For the most part, features fell into two categories: things they got right and things they hadn't gotten around to yet.
For example, I liked how they implemented automation, but at the time S1 couldn't freeze tracks. I liked the routing freedom, but hated the crude PRV. My conclusion was that Studio One had a long way to go before it would be in SONAR's class -
but if they kept going the way they were, eventually it would be awesome.
Remember, S1 is the new kid on the block. It's less than ten years old, much younger than any of the major players. Now, at version 3, they've addressed many of my earlier complaints. MIDI editing is better and you can freeze tracks. In a few areas they've even surpassed SONAR, such as the ability to split signals for parallel processing within a track. They have a feature I've been begging CW to implement for years - start and end markers.
They've still got a way to go before they catch up on bundled instruments and effects, but they're working on it and seem determined to match features with every major DAW. For that reason, I think hitching your wagon to Studio One is probably a safe bet for the future.
That said, I have no intention of switching at this time. SONAR does everything I need it to do, but most importantly I know it well enough that it's transparent to the creative process. Microsoft could break it someday, but that day is a long way off and may never even happen at all. More likely is some future plugin incompatibility, but I'm not concerned about that because even after all these years collecting plugins there isn't a single one of them that I couldn't do without.