I've only used SYP once to build a shop cabinet with dovetailed drawers. Others may like SYP but it was awful to work with for me. Maybe I just had bad boards or something.
Jim
SYP has it's own character that's for sure. Its not poplar and its certainly not whiite pine. Looking at wood not plywood for joinery, it's common to see it in our area based largely on its abundance. That doesn't make it the perfect wood for every task if you want to optimize your labor efforts.
When building a drawer perhaps for a period piece, its not unusual to find pine of all sorts used. I think the old timers used what was available in the shop if it was dry and stable. I've seen beautiful mahogany or walnut case pieces built with pine and poplar. They both work so I guess they used what was ready??
White pine is my first choice for chair seats on Windsors. It carves easily and it absorbs the shock transferred to the seat where the maple leg is tenoned in to the holes. Don't want a brittle joint. Yellow pine could be used but its a bear to carve. Poplar is usable but the density and hardness of poplar has to be considered with each board. Its a wide range in my experience. There are other woods to consider for the seat like butternut but its cost prohibitive in most cases.
White pine is unbeatable for window sash that you will shape with a moulding plane or router. The edge benefits make it my first choice.
Strength and wear: Yellow pine is tougher by a good bit. Its a much stronger material than white pine. For outside use, I will use yellow or white but when strength is needed I lean towards the SYP.
When I built my small shop, I used all SYP I found from a house tear down. The wood was all 2 x 12 so I ripped all the stock to frame it. That took a little extra time but I was able to build 10' walls and an upstairs that was usable with common rafters at a 12/12 pitch. I am so glad I did not truss this upper deck out. I have so many things I don't use everyday and they go upstairs allowing me more room in my small working shop.
Cost: Here in Durham, we have a source for SYP that I think is just unbeatable. Ricky Pope sells high quality 13" wide pine cut on a bandsaw mill for about 1.10/bf. You can do most anything with it and its dry and stable. I might add.. he's hear on the site and he's happy to work with you on big or small amounts.
I'll leave plywood for another thread.
Dan