Hugo,

It does seem that dynamic SP would share the same characteristics as dynamic SPT, in which case you'd have to ask "why are you doing this?" (And I suppose you might expect an answer like "because SP is always best") ;-)

Re RVs: they're not better than SP or SPT, they're just a different approach, with different advantages and disadvantages. I don't think I'd consider a RV for the example in this thread- unless it has to work on multiple backends, in which case a caching/munging tier might be the way to go, using plain SPT or gendbc to convert between databases. The arguments to which you refer tended to be the opposite direction- generally "SP is always best" or "RVs don't scale/are insecure" etc etc.