I had a 2008 1200GS and the faults from the 2004 launch were still not fixed, I was lucky to have nothing major, but it still managed close to £2k of faults from 2 years old and 6k on the clock when I bought it and 4 years old and 20k on the clock when I sold it - had I had one or two of the common big ticket itemfailures (Final Drive, Clutch, Gearbox, ABS Controller or dropped valve) it could easily have £3k, £4k or £5 of repairs in that time.
The ealy 1200's were a disaster, they did get better but even 8 years into production the 2012 models still have weak final drives (compared to the Yamaha - they are much better than early 1200GS' - which had a shorter lifespan than a chain). I really wanted one of the last Aircooled 1200GS models but could not bring myself to take the risk of getting a lemon. There is no way I would ever trust a launch model BMW, they have already recalled the latest WC GS for oil pressure problems before any have even landed in the dealers showrooms ???
Anyway, I came from sportsbikes / sportstourers to the GS and onto they Yamaha, as mentioned I loved the 2012 - 2012 GS to ride, but did not trust them, this left me looking for something similar, I also really loved the Guzzi Stelvio, a wonderful bike, but the Mrs did not like it, and I was a bit concerned about reliability and dealer backup, my guess si they are more reliable than BMW, but the one thing BMW are good at is fixing things fast.
The Triumph was just launched, this put me off a bit as it is their first single sided shaft bike, and their first 1200 motor, there were no deals to be had as they were selling well, and one of the reasons I wanted a "GS Clone" was the performance is perfect for me to have a bit of fun without doubling the national speed limit all the time, the Triumph is really a comfy sports-tourer IMO, sportsbike power and chassis geometery dressed up as an ADV bike - nothing wrong with that and when I was looking to move off my ZZR1400 a few years back it would have probably been perfect.
The Yamaha seemed like the best allround bet, the Multistrada had the handling and performance (but Ducati ownership scares me as much as BMW - and this thing would shred my licence) the GS has a great feel and sharp handling (but reliablity issues) the Triumph looks a good bet (but not the safest)
The Yamaha seemed to guarantee reliability and did nothing badly, it does everything well, never the best, but always pretty damn close and without any real weaknesses except price (in the UK where it is a lot more than the Triumph and BMW). If choosing again I think I would still take the Yamaha as I think I could keep it for many years and just keep updating it