Tripecac
I'm sure I'm not the only Sonar user with a "wandering eye". 

Well, that's why I said "You may find that rewiring Reason into SONAR gives you the best of both worlds." To continue your analogy, you might consider having a mistress as well as a spouse  

Gosh, I barely have enough time for the spouse!  Imagine having to split time between both!
 
For a while there I thought Project 5 would become the mistress... But that didn't happen.  For hardly anybody, apparently.  Talk about wasted development time!  In retrospect it seems like Cakewalk went into competition with themselves.  And then axed the worse-performing product line.  Weird.  I know Microsoft does that internally (or at least did in its heyday) but think of all that marketing and support time wasted, down the drain.  Perhaps that contributed to the belt-tightening and a reduced focus on perfecting MIDI sequencing tools.

Tripecac
I use Adobe Photoshop.  Super-powerful, but a bit slow to load and a memory hog (compared to Macromedia Fireworks).  Are you using Premier?  Is it similarly slow to load?  Did you try out Audition for MIDI?

I use pretty much the complete Adobe Suite. Not too bad for memory, just have to read up on the tweaks. Helps to have multiple SSD hard drives...for projects as well for scratch disks. Only ever did midi with Cakewalk products. Never saw a need for any other (except maybe Acid Loops). I don't do a lot of music anymore, unfortunately. Too busy making a buck at multimedia, video & voice over work in the eLearning industry. Audition is funky, to me. Premiere as well, but the learning curve investment is worth it due to the integration of the products. Very cool to see tweaks to files in other programs show up in the one you're working in.