I have never owned either a Vigo or SWB 70 series, and although driven them both but never on really long drives either. But Vigos are very stable vehicles. Infact they are the premier choice for all extremely fast rally drivers in Pakistan because of their stability. Granted the vigos used in rallies have upgrdaed suspension, but then so do most others in rally circuit. Toyota Surf on the other hand have had strong history of roll overs in rally circuit for one reason or the other.
TLC 70SWB will not be as stable in comparison, because of SWB, higher COG etc, But still very stable for normal commuting and long distance travelling. They will be very good offroad as well .
On straight fast motorway type road both of them should be reasonably safe at high speeds upto 120-130kmph. One needs to remember they are not cars, but trucks, they are big n heavy and will behave dramatically different to sudden steering inputs at high speed. They do not slow down as quickly. Vigos mostly have accidents, because they have become so car like to drive over last 20 years with IFS and plush interior, drivers tend to forget they are driving a truck! In city speeds are lesser n you get away with sudden turns etc, on motorway you need to plan n drive accordingly.
Only 15 years ago, most of these Civis n Corollas were only 70, 80 or max 90hp, now the 1.8s are hitting 140hp. And similarly the older Hilux double cabins and TLC IIs with 2l, or 3l were merely 70-80 or 90 hp, now these 3.0 d4d are above 150hp and some reaching 200hp! So people are driving much much faster and probably not properly prepped for consequences!