Hi Lewis. I had a
Gotostar (GTS), an early version of
Goto Nova (GTN), yes you need
the ST4 adaptor as the set-up has no ST4 port. Although Telescope exppress may be selling them with the adaptor module?
Specificially the difference was the GTS was serial and the GTN USB however this was done with a silicon labs USB to serial converter inside the handset so...they are the same ...essentially. Although they have now changed display sizes since earlier versions and firmware has changed a lot. Also the GTN has a battery backup Real Time Clock ..so it remembers on re-start what time it is and lat/log you are at.
I liked the GTS, it worked well. Slew was a little noisy but that was because it was 512X sidereal! Nice handset layout and 8 line LCD readout and 32bit processor. Price is right to. I think they changed some of the original brass milled spur gear with a cheaper cast gear and there were some people not happy with this. However I think it's pretty much the same as the vixen spur gears so replacements are available all over the place.
I don't know how their ASCOM driver are going atm, they did have trouble at the start (year ago now) but they put a lot of work into this and my last ASCOM and firmware updates was really working well.
I reckon for the price...you cannot go wrong!