Rather interesting. I tried the 2 stroke in my 4.2TDi and found no difference in performance, economy or noise so have about 7 litres of oil for my wiper snippers.
I used Chemtech additive on last fill and performance has improved but that might also be a result of a good hard run over on Fraser's loose sand for long weekend which has cleaned out a bit of crap built up over recent months of short trips.
Don't think any of these products are VALUE for money if you have good diesel to start with and good filters.