Prior to our old BU Armory track being torn down, there was always talk about the track being short, because times there were faster than most places. In fact, Joe Piane at Notre Dame was able to get his 300m track to be "graded" at the same index as the BU track (if I remember correctly). He felt our track was as fast or faster than his 300m flat track.
When we were one of the few banked 200m tracks in the country, we had entries from all over the country, including Oregon, Colorado, Florida, Michigan, etc.
When the new facility was built, there were many more 200m banked tracks competing for the top athletes, including the Armory, Penn State, Washington State and eventually Arkansas.
In the early years of our new facility, we actually had a decline in teams coming in with the Terrier Classic suffering the most downturn, as other facilities had top competition on the same weekend. The Valentine Invitational became mostly an outlet for D2 and D3 teams to get final qualifying marks prior to Nationals. So for a few years after the new build, we actually had slower performances, despite our thinking we had built a fast track with a true "bounce".
That all changed when Rupp came to the facility and ran his mile time. Other teams and coaches saw what could be done at the track. We had built a top notch track and they came (an adaptation of the Field of Dreams line).
In the last few years coaches figured that it might be a good idea for their 3k and 5k runners, coming off XC could come into BU and get an early qualifying time.
My point being that, yes, the track is fast, but it is fast because fast people run here against each other and there is now the same hype of good marks that used to exist when we were the only show in town at the old Armory.