I've got to say upfront that I have very little experience with the brands you mention - except seeing the MDC at a Rays Outdoors type of store and not being too impressed with the quality of the floor, window sizes, height inside etc at that time. This was after we bought our second hand Vacation Campers so I was/am bias
We've had some cracking storms and not a drop inside our tent. Other owners of these brands may say the same.
At the end of the day it comes down to whether you want new with warranty etc or second hand. These brands seem to be stepping up their quality control lately so maybe less of a worry. check the quality of the canvas, paintwork finish, locking mechanisms, quality gas struts, dust sealing and the hitch they provide (some can be a right pain to hook up to the car).
We're coming into Show Season - so if possible go and check them all out at the same time. I won't get into the import v Ozzie comparison, or I have this blah blah brand so you should too.
My best tip is - don't go for the bigger the better set up. Too many poles, too much time and less time enjoying yourself.
And make sure your tow vehicle is more than capable and allow for the additional cost of setting it up with electric brake controller and/or Anderson plug to the camper to charge the battery when on the move (handy when travelling and moving), solar / fridge and all the other bits and pieces which can all add up pretty quickly if you start getting keen - like the majority of members here.
Your thoughts?