The Mak will have better resolution. Resolution has to do with the
distance between the boundary of the element collecting photons, and
little or nothing to do with the central obstruction. The primary
effect of the central obstruction is to reduce contrast. The loss of
light resulting from the central obstruction is probably in the
neighborhood fo 10%-12%. The Mak will still collect move than twice as
much light.as the 80mm refractor I'd go for the Mak (and in fact I
have a 5" Skywatcher Mak, purchased from Khanscope in Canada for $400;
I'm told it's quality is much better than the Orion version.)
Clear skies,
Shneor Sherman