1: A top notch grinder under $300 will be very hard to find unless it is second-hand and even then that is cheep (new burrs would be needed at an additional $$$)
2: For under $200 the next would be teh EM0450 or Em0480
However it also depends on what machine your talking about....
Your profile / sig does not identify what equipment or coffee machine your talking about.
Further more, the issue of stale Vs fresh beans can also be a factor as a cheaper grinder will not manage stale beans as well as a higher end unit.
Thus teh issue your seeing with your BCG 450 could be related to the beans and thus a slightly better grinder ie. Em0450 may not solve your perceived problem..
* A poor tradesman blames his tools :D
Yep better tools help, but one needs to be able to truly identify the root cause - otherwise a new pile of new tools may not solve teh problem.