I got the Aqua Magic V and I like it for several reasons.
1. You can get to the bolts to clamp it down without having to get on your head and having long extension (I didn't) to get back left bolt off.
2. You don't need small hand to put bolts on in front.
3. The water supply line is much easier to hook up. I took the copper pipe off and put a PVC adaptor on it that allowed a brass barb fitting to be used and got about four feet of Tygon 3/8" web reinforced tubing and left about 4" of copper tubing on past the cut off valve as a stub to slide the Tygon over. Of course both ends have pipe clamps on them.
4. It is very easy to operate with the left hand when you are half asleep in middle of night.
Note: the threaded part on the Thetford is pretty tricky to get Teflon tape around and I had just a trace of water come out of it and run down the pipe so I cured that by reaching under and cutting off the water supply valve when it was not in use. In the interim after a couple weeks use I don't see/feel any more water so maybe it finally "seated" and sealed up??? I was at plumbing supply the other day and got a tube of pure white Teflon Joint Compound that I will put in rig "tool box" to have for future use if needed.
I am doing a lot of work to this rig to get it "right" and am creating a tool box. I have lots of tools so every time I need a tool for something and have two (or more of them) I leave one in rig in one of the big pull out bins under the couch.
I have things like a soldering gun (twisting wire together to make a circuit doesn't cut it) so I solder everything I splice before taping. I got it on the road at a yard sale. Already had a pencil gun but it wouldn't get hot enough to work on 14 GA wire when I had to repair charger I took along. Got a Zylis aluminum vise to clamp on fold out table to hold stuff working on it etc. Got a box of various screws and nuts for repairs etc. Jar of bearing grease, work lights, Dremel tool, 18 volt drill, tire plug kit (professional grade), small air compressor etc.
Extra Tygon tubing 3/8" and 1/2". I like the Tygon better than copper because it was/is easier to run and I can see if there is any water in the line left when I winterize it.
There is a Thetford sale on the till Sept 30. You can go to their on line website and get a form for a $15.00 rebate till Sept 30. I did not know about the sale when I bought it and when I tried to register it the website said I had entered bogus info as to rig ID, VIN number etc. I called and apparently it is set up for modern VIN numbers (mine is 76 Sovereign) so I had to call them to register.
I was asked if I still had the box, I said "NO, there was no reason to keep a empty throne box." They want a bar code cut off it. Also they want serial number (on top at back behind seat). Also they want a receipt. I have just got another receipt and getting ready to send it in. I was told they want the bar code and receipt because anyone could get a receipt and send it in and they were evaluating each case. I got mine from authorized dealer listed on their website so hopefully there will not be a problem.
I kept the old throne (seat was cracked) in case I can get another seat. Thinking of using it in a cabin with a water supply from trapped rain water held in a tank at higher elevation. For a "tank" I will use 4" ribbed plastic with drain slits buried for 25 feet which should work fine. A friend did this starting with a 20 gal plastic drum and a drain line. Works like a champ. Been installed for 12 years or so now.