An Ultrdot 30 or a Matchdot?

I am interested in buying another UltraDot 30mm. I have one on my Nelson and will want one for my 45. The Matchdot recently caught my attention however. What are the advantages of the Matchdot compared to the standard UltraDot 30mm? Other than the ability of changing your dot is it built better or offer any other form of upgrade over the standard 30mm?

No caps, the windage and elevation knobs are super handy.

The Matchdot has different size dots you can change and use. Could a shooter change to one size for slow fire and another for another match? Or do you risk a loss in zero of any amount by changing the dot?

Definitely no change in zero when changing dot size.  I was using 4moa at 50yds and 6moa at 25yds.  It doesn't make much difference in score but it seemed to help me relax and keep the trigger moving in sustained fire rather than trying to "dress" the shot. However, once I noticed the slight negative magnification on two of my Ultradot's, I had to switch to Aimpoint.

The variable dot size is the main reason I went Matchdot. I like as small a dot as the light conditions allow.

I have 3 Matchdot II and really like them  I set the elevation turret to Zero after sighting in at 50yds then record the settings for 25yds, 20yds, 50ft  and 10yds.  I have ran a ladder test running the settings up and down and windage stays constant and return to zero is right on.  I have noticed a very small parallax so I tend to keep the dot centered.  Don

I have the older Match Dot, dot size can be changed but only dot size no retical change available. I can't complain, it works good though I use one dot size. I got it from a club member when the Red Dot I was using was giving me problems, availability was the reason I got it rather than dot size adjustment.
 I have heard others complain about the newer Match Dot and a while ago there was another thread here about problems associated with Ultra Dot scopes including the Match Dot 2 you might want to look at that thread.