Hi DaveO. The optics of the scope are the same, though the focuser is a dream (I did a bit of research on it when I was thinking I might need to upgrade my 80 focuser for upgrade. I didn't need to but I still thought long and hard about it. See
here
I have two sets of losmandy rings and if I needed another set of rings I wouldn't think twice about getting another set, even at that price. They are weighty though and you need a losmandy dovetail to mount them but I wouldn't be without mine. Check them out
here I've not compared them to other topend guiderings.
The compression is a brass ring inside the eyepiece sleeve that takes the place of the one or two thumbscrews that tighten on eyepieces to hold them in. Pretty much a standard for higher quality focusers etc. Tensions evenly around the circumference of inserted fittings rather than having the thumbscrews push it up against the other side of the sleeve. Much more secure, and you can rotate the eyepiece etc without loosening the compression ring (as long as its not too tight).
The focal reducer field flattener speeds up your scope (less exposure time) widens the field of view (can be a + or a - depending on what you want to image) and flattens out the field curvature of the imaging lense. Often highly desireable for medium to slow f/ratio scopes, particularly SCTs and Refractors. From what I understand Newts use coma correctors which are similar (flatten the field) but don't change the f/ratio (Don't know newts so I'm only assuming here. Is this correct anyone?)