I shot the 108 Bergers and 108BT BIB's (a few matches) all last year at IBS in my LG and HG in 600 yard competition, but switched to VLD's during the Nationals because of the extreme winds in S.D.
When I started loading for the 108's I quickly learned they are much easier to tune than VLD's. In the 2 barrels I shot them in they did not seem to be sensitive to seating depth or powder charge like the VLD's. I could not see much difference in groups at 600 yards during tuning. But you will need to drop about 1 grain in powder compared to the VLD's due to longer bearing surface and extra weight. They show a consistent pattern where the VLD's lots of time's have flyers. By this I mean, if both the 108's and 105VLD's shoot a 2 inch 5 shot group at 600, the 108's will be evenly distributed in the 2 inch circle. Lots of the time the VLD's will have 3 or 4 in one inch and one or 2 flyers making the group 2 inches. But when the VLD's don't have a flyer, look out!, this is when most of the World Records have been set and have come from behind and won the match ( Yes, I am talking to you Mike Davis).
Mike and I talked about this subject last year. The 108BT's are great until the wind gets up. They seem to get blown around more than the VLD's. A 1/2 extra at 600 yards these days means the difference from winning or being put middle of the pack. So, the Ideal would be have 2 loads. One would be the 108's for mild days, and 105VLD's for those windy days. If you don't have time to tune the 105VLD's (and lots of the time this is tuff to do) stick to the 108's they will save you alot of headaches and will stick close to the VLD's in most conditions.
I almost forgot to mention. As the temp's and humidity got up in the summer time last year in NC, the 108's did not perform for me as good as they did during the cooler, less humid month's. I retuned them, but never got them to perform as good in the summer as I did in the winter and spring- even when there was no wind. I cannot explain this except maybe because they have more drag than the 105VLD's. The extra humity may have had more of an affect on the 108BT's than the slight difference in BC shows between the two bullets. The VLD's seem to bore through the wind and humity better than the 108BT's.
These finding are my own opinion based on many, many groups shot tuning and in competiton and in several barrels of various manufacturers. Hope this helps and does not add complications to your choice. Try both bullets before you buy alot of bullets, your rifle will let you know which it likes. Lots of the time, a particular barrel will shoot one well and not the other, a few will shoot both well. I have also found just about every match barrel will shot the 108BT's well, not all will shot the 105VLD's well.
Samuel Hall, Boonville, NC