Was your purchase worth it?  I suspect we are all a little afraid of this question.  There are several purchases I've made for this hobby which I'm not convinced have paid off in terms of image quality improvements.  This post tries to address this question head on for my own recent upgrade.  As such, it's not the highest quality, most-integration, excelsior type of image, but I hope it provides some information.

I recently purchased an AT8IN imaging Newtonian, second-hand.  This will replace my long-suffering Astromaster 115 and would address several of the deficiencies in that rig.  The seller had already obtained several of my desired upgrades, so getting everything in a single package was a major benefit.  These included:
1) larger aperture to support 2" focuser drawtube (addressed focuser sag and light-loss), 
2) Baader MPCC to improve field of view, 
3) Rigel systems n-Step focuser to improve automation and repeatability of focus.

I had originally targeted an AT6IN with only 6" of aperture.  This would have reduced the weight of the rig significantly compared to the AT8IN, but the used market right now is one where you take what you can get.  This significantly loads (overloads, probably) my little Skywatcher EQ5 mount, but I gave it a try anyway.  This required some improvisation for the counterweights and some very careful balancing in both RA and DEC.  A benefit of the AT8IN is that it is large enough that I'm comfortable setting the camera and filter wheel down toward the mount axis, as opposed to some odd angle to the side.  This really improves my DEC balance since most things are now symmetric.

The MPCC is a major upgrade for me and one long needed.  No 1.25" draw-tube diameter coma correctors exist on the market.  None.  It would be a major lift to modify the Astromaster with a 2" focuser,, so the AT8IN is a major improvement on two counts: a) I get to have a coma corrector of any kind, and b) a 2" focuser has much better tilt control than the little 1.25" one I've been working with.  One of the image uploads directly compares the tilt numbers between the two scopes.  It shows that the Astromaster had "severe" tilt while the AT8IN has "almost none".   Likewise the aberration plot comparison shows the marked improvement in star shape over the field of view.  I'm noting that the AT8IN images are "first light" with the MPCC.  After some digging, it is apparent to me that my back-focus is off by ~2mm and I will be working to fix this.  I suspect I will get better star shapes in the corners with some additional adjustments with the MPCC.

A major problem in recent images with the Astromaster has been the enormous star size.  I had suspected that much of this was due to a few intercepting surfaces in the Astromaster's light cone and was hoping the AT8IN would clean it up.  One of the revisions takes my recent M45 and adjusts it to make a direct comparison with this image.  This required a rotation and scaling.  I've scaled the Astromaster UP 200% and the AT8IN image down a little more than 50%.  Processing is different between the two, of course, but I think the image is pretty clear in terms of quality.  In particular, HD 23463 makes a nice comparison near the left-center of the image.  This is a triplet of stars that the Astromaster image can't really resolve, but the AT8IN resolves well.  

In terms of mount performance, this is still an investigation.  I was having a lot of issues with the mount controller and had to toss a number of subs.  I am also unfamiliar with using "autofocus" and this caused some issues.  I recently re-lubed the EQ5 and this, in addition to carefully balancing the rig, I was able to achieve similar guiding numbers as with the Astromaster (about 1.3" rms).  A good polar alignment was also achieved for this set of data: <1'.  When I have more practice with the mount, I'll have a better idea of whether I really need a more capable mount to handle this payload or if I can keep running with the EQ5.

I hope this set of comparison images is helpful to all those that are considering a similar upgrade.

Comments and criticism are welcome!