Whether it is sweeter or not will depend on the tobacco you extract. I'll tell you though, your first extract will probably smell like sweaty socks, but I got over it.
What I've been doing lately is going back to commercial tobaccos. There are some very good ones out there, but I'm a lazy DIYer, and started extracting because of all the NET talk going around. To tell you the truth I've ended up tossing most of my NETS. I kept 4 of them 'cause they taste too good to toss
These are:
American Spirit Natural(from the rolling tobacco, not the cigarettes)
Dunhill 965 pipe tobacco
Mclellands Syrian Balkan Supreme pipe tobacco
Peter Stokkebye's Golden Leopard pipe tobacco
Everything else was redundant, and had equivalents in the commercial flavors department.
But that's just me, and I'll be learning this stuff until I croak.