hi,
all engines are, in the end judged on how they do the 'job' for which they were designed. the RB26DETT was designed to curb the dominance of the European engines [porche,ferrari,BMW etc] in Gp1 type racing. this it did very successfully. so by that measure it was a very good engine; it has the 'runs on the board'. it is the heart of the Godzilla legend and it created a cult following around the world. it is a famous engine. the new VR3.8 is designed to compete with the super car engines of the world and on paper, it looks competitive/impressive. but it is still only 'on paper' so in my opinion, it has a lot of hard revs to do out in the real world before it can be compared with the RB26.
let's have this discussion in five years time; if the new engine has created a global cult following, if has been given it's own mythical reptillian designation and doesn't meekly take the Godzilla label to gain undeserved 'street cred', then it will have drawn level with the RB26. now to get past the RB26, I think most will agree, is going to take some pretty serious motoring.
having said that, I have just returned from Japan where I made a point of going to a presentation of the new RB35 and later to the Nissan showroons to view the six new colours. for those that are not impressed with the car after seeing only photos I suggest you wait untl you see it in the flesh; this is a seriously beautiful and muscled-up car. also sat down and watched [in the showroom] the video of the car's Nurrburgring trial; powerful!!.
regards