I have an Ultragauge in my truck and I mounted it above the rear view mirror. I don't know much about the Scangauge but everything I read on the Tacoma forums said the Ultra was the way to go when it came to information that was displayed and the cost. It's a little finicky to get setup, but there's pretty good instructions online on what to do and I'm sure a Land Cruiser forum will have vehicle specific setup available.
I've got the ultraguage in my '95 landcruiser, very handy to have to check engine temps, fuel consumption, many other channels. No experience with the scan gauge except it was twice the price when I bought mine. Ultra has a new one now that works with a plug-in and your phone. About the same price, I think it's called blue ultra or something.
I really like my Scanguage II, but would really consider an Ultra if i did not have it. I have it hard mounted in the rig and use the cheap OBD plug-ins and bluetooth with a Torque app in all the other vehicles.
I use a scanguage II in both the Subaru and our Tacoma.
At the time Ultra didn't have codes for Transmission temps from Toyota, that was a big reason why I got it. During camping/ towing season I wanted to be able to watch what was going on. There are way more codes for Toyota and Hondas than other makes, not too many other than the standard ones from Subaru. It would be sweet to crack the subaru differential codes and get a live F/R distribution reading..