Have to put my 2 cents in here.
I have owned 3 Beta 200s. First was a 2010 which I liked and was very easy to ride very linear power.
2nd was a 2016. This bike also very well behaved. I noticed a great improvement as the engine cases were specifically designed for this size engine.
And because I liked the 2016 so much and that it was so easy to ride I just took delivery of a new 2017. Only thing I changed from stock is the fast throttle.
Prior to the Betas I always owned GG 250s which I also liked very much but during trials competition I score much better on the Beta.
I have tried a Sherco 125 in the past for a short time and really did not like it as at low revs it was not very responsive and it definitely had a hit at higher revs
For someone just getting into the sport that wants to compete a 200 will IMO be a great easy to ride bike. Power delivery is very linear.
Best of luck with whatever you decide