have ridden both relatively recently.
rode the BOB 137 and harley 139. I normally ride the LF witness, so my observations will be based on the LF witness traits.
BOB was noticeably looser than my witness. Probably not as loose as the LF trip, but it was very loose. It has a lot of pop, it was fun. The landings felt similar to my witness except it was more loose. It released very easily off the wake. I had to be really patient when edging in so it would not break free on me. the same way I had to ride the trip.
Harley. I immediately thought "ronix covin" after my first jump. It is a fast board and lands fast, it tracks well and holds its edge very easily. The pop is consistent but it is mellow, typical of a "continuous rocker". It releases consistently off the wake but later than the bob, trip, or witness. It is a very consistent board all around. After I took a set on the harley, I rode my witness and was riding so much bigger… probably because I am sued to that board, but the pop on the witness was greater with less effort.
Hope this helps… the witness is going away so I am going to have to look for a new board soon… between those two I would ride the harley.