parish8,
I really like the power usage of the '99 yz125. It has a great low end, for a 2-stroke. Thing is, you won't find a 2 stroke bike that will be like riding a 4. The beast doesn't exist. (KTM 380sx riders may disagree)
You will be happy riding any two-stroke bike, they are great fun. I happen to love the top end zing of my KTM 125, but it requires alot of clutch fanning and needs a bit more finness in turns than the more tourqy bikes.
You will be happy with a '99+ yz, but be warned....hard riding of these bikes requires a bit more maintenance than other bikes. The '99 is prone to crank failures without proper maintenance, as well as quick turn-arounds on top ends.