I'm going to start a fire here but I never saw a difference between my SNS starters and stirplate starters. To my untrained (but experienced) eye, my stirplate starters looked more foamy and active. The beers did not seem different, really. The SNS starter did not produce a better beer although it did produce a good beer. But same with my stirplate. To me this always seemed like a solution looking for a problem. I realize I am not a yeast lab scientist and I also know that a lot of study and effort went into those findings. I was just always very satisfied with my stirplate starters. My 2¢.
I think maybe my SNS beers turn out better, but I've never done a side by side. For me, one of the big plusses is that I find it faster and easier.
I have notes about some stirplate beers where I pitched the entire contents of the starter and those beers were spectacular. I have made 4-5 SNS starters and again .. good beers. No complaints. But I didn't have any complaints about my stirplate starters or beers either. It wasn't an area where I was doing homework and looking for improvement.
I'm of the same opinion that you should pitch starters at high krausen. The stir plate work just as well a SNS method, the key is to pitch very active yeast. I don't see how SNS could be easier or faster, in fact I think the stir plate would be easier since you can "set it and forget it".
I brew a lot of lagers with 4 liter starters and I don't want to pitch the entire starter. I crash cool the starter at high krausen and never let the starter hit final gravity. The starters will actually show some krausen at 33-34F (Wyeast 2124), I decant prior to pitching. Since adopting this method, my lag times on my lagers are @12 hours at 48F, down from 18-24 hours
I also make starters with dry yeast. It works really well to build up the yeast count. The viability is very high, but keep in mind the yeast should be treated as a liquid and requires aeration at pitch. The idea you can't make a starter with dry yeast is an old myth.
If you want to preserve yeast longer you can add a buffering solution to the yeast slurry. KH2PO4 at 2-3% solution will extend the viability yeast. Here's a white paper from the late 40's on it:
https://onlinelibrary.wiley.com/doi/abs/10.1002/j.2050-0416.1955.tb06256.xHere's a Master Brewer's podcast on the same subject:
https://onlinelibrary.wiley.com/doi/abs/10.1002/j.2050-0416.1955.tb06256.x