I'll be honest - I'm not a fan of sashing. It's a lot of extra effort for not much extra, and also, if feels a lot like binding.
Still, it can make a simple design a bit more interesting. Make a sashed 9 patch, and then make it dissappear, with a bit of extra sashing, and you've got a very lazy leadlight style quilt, unless you use white for the sashing, in which case it doesn't look like leadlight at all.
By my standards, it's big. 165cm each way, which I know isn't that big by other people's standards, but it's still too big to quilt doing wavy lines on my little old machine. It was on my finish list, but I'm actually seriously considering getting it properly quilted. If I could free motion I'd do that, but for that I'd need to send my machine off to get serviced, and, you know, learn how to free motion, and then get confident enought to do a big project, so maybe I'll just pay the lady at Stitch and Knit $90 and tell her to do whatever. I'd be happy with a stipple really.