If that means I can install 2.8 alongside 2.6.11 (As full install - not portable) then I think I'll use your version. It'll give me chance to experiment.
not sure if i must define portable for sure may be easily used as portable
But as far i know the full -install version doesn't offer any advantage, only some disadvantage:
the only drawback i know is from using portable apps from external drive , in that case the usb connection may be a bottleneck and so slow down respect the full install version, but if installed on the main drive there is no any difference in speed
about disadvantage of the full-install version ,at least about gimp, in years that i contribute to gimp help forum, all weird problems that could not be solved in any way where simply solved by replacing with portable version
less generically the normal version are much more easily victims of dll conflict (not only with other version of gimp , simply if some other program use similar dll the full-install gimp may become very quirky when not totally unusable