[glend (Glen)]

The MN190, with the small secondary, is fine for sensors up to APS-C size. No vignetting with my Canon 450D (APS-C).
I considered upgrading to the TS Photoline 130mm, as it uses the same focuser and reducer (3" Photoline) as my 115mm, but could not justify the cost differential at that time, now its cheaper. Consider that the MN190 gives you 1000mm fl, the TS 130 would be 910mm at native f7 (reduced to 719mm, f5.53 with the Photoline 0,79x reducer). I see they have reduced the price of the TS 130mm APO with the R&P focuser, it looks a pretty good deal for only 300 euro more than the 115mm - i am tempted as all my gear will fit.
Don't forget to consider the cost of buying the reducer. I have both the 0,79x reducer corrector and the f7 flattener.
You would probably need to replace the MN190 focuser with the new Moonlight one. The new adaptor suits the MN190 much better than the original adaptor, which did not allow focuser centering exactly over the secondary.

And Dave, the Astrobin link is my signature line below here.