I've read that out of all flavors bakery and chocolate are the hardest to approximate and from reading reviews I think that's probably true.
Like you can extract the flavor of a fruit or spice directly from that fruit or spice, but you can't really extract the flavor of bread directly from a piece of bread (as far as I know). I've only tried a few bakery vapes, but to me they have a sort of "murky" cloudy taste, it's not a crisp clean flavor like you can get form a good fruit vape for example.
As far as really sweet flavors go, I love to eat really sweet things but as a vape anything super sweet seems too sickening for me. I like the mild sweetness that comes from a fruit or lighter creamy desert flavor, but I received a sample of a very sweet butterscotch and a s'mores flavor so I tried them and it was so sweet, (even though it came form a high quality vendor and was well made for what it was) it was just sickening to me.
I can't imagine vaping anything as sweet as that for more than a few puffs.
I think it works better if the sweetness is lighter or mitigated by a more earthy note or the bitterness of a spice or something.
Edit: There are some "dessert" flavors that I love though, but they aren't that sweet. The desserts from Nirvana Vapors stand out that way, as does the Free State vapor flavor I just tried-The Nilsson, it is like barely sweetened light and fluffy whipped cream from real cream with a zest of lime and a hint of vanilla and little flecks of pie crust here and there, wow this is awesome, I actually wish I could eat this.