Mine pretty boring but WY2124. Mostly because I use it so much and understand how it operates. I've been using the same strain on 12th gen right now and under a microscope no signs of mishapen cells, it is a powerful fermenter, and super clean Also seems to stay viable for a long time, last cell count (yesterday) was at 95% viability and that was after almost a week after harvesting. I have another pitch on the way so I am going to be starting over soon but such an easy strain to work with.
The one I have a love/hate relationship with is 1214 and I use it all the time because it works well in my #1 selling beer. It is stubborn as hell, refuses to drop out of suspension even after heavy fining but works great when your flagship is a Belgian Wheat beer. Seems to become less flocculant and more dusty over time as well.
The cells start to become mishappen after a few gens so I am constantly having to order a new pitch.
Sean, I would think the biggest concern with blending those two strains would be harvesting since the 3522 is so much more flocculant.