Vests are great for mid level activity, stop and go stuff, level or downhill walks, stalks (make sure it's a quiet one, fleece or wool), etc. They vent well if you exert a bit but help keep core warmth. And hands down easier to shoot the bow with or any other kind of moderate activity really. Currently mine is fleece (not even sure what brand, it's old) but am digging through the furniture cushions for change to save up for a new Springer vest. All those give me a dead quiet layer system for active bowhunting. If you're moving much at all you can stay fairly warm with that. My thermostat is set pretty high though, blood is on the thin side when cooler weather hits.
Usually go with a good base layer and a heavy shirt for second. It gets a little more chilly the vest. My old system 4th layer was a Rivers West Law jacket that did double duty as rainwear and outer layer over the top of everything else when it got colder. Served me well in late sept MT and ID when it would get into the teens.
The RW is about worn out, bit the bullet and trying a new system next. I've had a Yukon rain jacket that I'm really liking, have used it several times now (in moderate temps) and it is about the best raingear I've used. Packs fairly small, isn't too heavy, drys fast, cuts the wind, tough, so far so good. And I have an uncompahgre puffy that should be here any day now for when it just gets flippin' cold. Those two should give me a bit more flexibility over the RW as well as take me down to a little lower temps if needed. I'm not a winter hunter but on the mountain ya never know when it decides to become winter. Neither are as quiet as the RW, but I don't see using it much in quiet weather on a stalk or such. Mostly windy/wet nasty and/or cold.
Theoretically.....we'll see how that tests out.