Jackets on the VT's will generally be thicker than Vmax of the same caliber. The Vmaxs are usually shot in stuff that's like 1:10-1:14" twist barrels. The VT's are more like 1:7-1:10 and at 3000+fps the risk of blowing up warranted it.
That said, in most circumstances you're going to get very similar terminal performance to Vmaxs. In ballistic gel you're looking at about the same result-- Immediate rapid exansion/fragmentation, not many large pieces, and a temporary cavity that's 4-8" wide and usually no more than 8" deep (give or take). With the 6.5's and .30 cals occasionally you'll get the base of the jacket to hold together and penetrate deeper, especially on the lower end of the velocity threshold. 1900-2000fps impact velocity for reliable terminal performance. Some may dip a little lower than that depending on what they hit.