Tested the lot today!
I had to be sure I won't regret selling the GS a I have spent over £2k on extra's, all of which I would want to buy again if I went back to a GS.
My thoughts at the end of the day are, well confused!
Tenere
Hopping of my 2008GS the Yamaha seemed a shade lower (both seat heights are claimed to be 870mm in the higher position) but the bike feels a shade narrower between the legs making it easier to manage at junctions and less of a chore to mount.
Once rolling the bike feels as light as the GS, it has a load more low down grunt, and probably a shade more mid-range, the GS "feels" faster up top, but that may be more down to peakier delivery, the only comparison I did was pulling out of a junction and gunning both to a reference point and the result was they both hit about 80 from a standstill in the same distance, with the Yamaha feeling far less stressed by the whole experience.
The Yamaha has noticeably higher gearing (4k = 70 on GS and 80 on ST) and vibrates far less, so whereas the GS is feeling quite buzzy at 85, the Yamaha is dead smooth at 100, despite this higher gearing my instincts and (rather unscientific) roll-on timing (one-one-thoudand-two-one-thousand) had them very similar in the crucial 50-80 top gear roll on region.
The Yamaha engine is definately technically superior to that of the GS, I have no idea how they would compare on a strip / flat out on the motorway but I would be surprised if there was much in it, and my GS has de-cat headers and a accelerator module fitted.
The other key benefit is the Yamaha is much better at fuelling so will cleanly pull from under 2k in top and I suspect will be easier around town and driving out of alpine hairpins, even with the accelerator module the GS is not close to the Yamaha at low down manners.
Handling is very different story though, my GS benefits from top of the range Wilburs suspension and have been honed to just how I like 'em.
By comparison the Yamaha felt immensely slow to turn, so much so I stopped to jack up the pre-load a lot more which helped a fair bit.
Even so the Yamaha was still nowhere near as chuckable as the GS it still felt long and low and reluctant to turn and braking into turns dived noticeably more (but far less than you would expect for long travel forks)
It actually handled bumps pretty well, especially at the front, where I think the forks are better than the telever setup.
Unfortunately the roads were a mix of wet and damp with few completely dry corners so I never got to really get a feel for the Yamaha's handling, I reckon with time I may get used to it (or buy a shock with a ride height adjuster)
After the smoothness and grunt the most impressive thing on the Yamaha was the electronics, I have ridden BMW's with "traction control" and when it kcks in it feels like someone has turned your ignition off for a few seconds throwing you forward, before turning it back on again and sending you lurching backwards.
On the Yamaha you do not feel a thing, the light comes on but apart from that you have no idea it is even operating. To test it further I stopped in front of a patch of mud on a back lane, 1st gear and full throttle could not faze the system it just drove through the mud as if I had slowly ridden through it - pretty amazing, similarly the ABS is pretty unobtrusive compared the to GS system.
The one problem is it does seem to suffer from a rather terminal case of blandness and I fear despite being clinically good, ultimately it would just be boring.
Twin Cam GS
Next up I tried the latest GS, this felt familiar, but the twin cam engine is noticeably smoother, it has noticeably more low down power and will pull cleaner from a few hundred RPM lower - it is still nowhere near the Yamaha for grunt or smoothness though.
In the midrange it probably closer to the Yamaha than my '08 and up top almost certainly beats the Yamaha, I think it also beats the older motor at all RPM's but most noticeable is the extra bottom end and more free top end.
Gearing on the new GS is identical and by 90 it too is feeling a little buzzy compared to the Yamaha's lower revving dead smooth motor.
Handling is pretty much the same as my '08, the demo had ESA and although quite good and very convenient I would say the Wilburs on my bike rides bumps better and provides superior handling, the best way to describe the difference is it has the handling of the later bike in sport mode, with the comfort of it in Normal mode, it just operates on a wider range.
Also as I can tailor it more I have my bike a bit higher at the rear so mine steers noticeably quicker than the ESA in sport, with better feel and feedback. Either way though the GS in sport mode "feels" a lot more chuckable than the Yamaha.
This bike was the one that I would buy if starting from scratch and with cost not being an issue, it just makes me smile - as does my 2008, for all the flaws / character or whatever you want to call it the GS feels alove and involving.
Adventure
I also rode the GS Adventure, this bike surprised by not feeling huge or unwieldy, it definately rode bumps better than the stock GS (as good as my Wilburs setup) but it was at the expense of feel and turn rate, it was not horrible, but lost that lovely sporty feel the stadard GS has.
If I wanted to ride across deserts this would be the bike to do it on (assuming the FD would last the journey) but for my normal riding and touring to and around the Alps I would stick with a stock GS.
Not sure where this leaves me, the latest GS is not worth the £3k+ it would cost me to move from a (well sorted) 2008 model to a used 2010 model.
If I was a new buyer I would prefer the later engine, but would not pay a huge premium to get it, the new motor is just a bit better in every way - overall a good improvement, but not revolutionary.
Buying new the Yamaha is definately the best value, but possibly least fun, either way I a not in the market for a brand new bike right now.
I may however do the swap deal, or sell my GS privately and buy a Tenere as I think the only way I could decide if I would prefer the Yamaha is to own one for a while.
Still got the problem of if it turns out to be too bland I would be wishing I had kept my well sorted GS
