I thought I'd update this with a little feedback from the test.
In the end we took out two bikes - the Multistrada 1200 S and the Hyperstrada. I was first on the Hyperstrada, and it was a very odd feeling at first, as you're so upright and forward it feels as though you're sitting on the front wheel. The engine is pretty lumpy low down, and as you move up through the revs there's some fine vibration through the throttle - not enough to notice but enough to start a little numbness and tingling after 10 - 15 minutes. The wind protector flexes a lot and doesn't really offer the protection you'd expect relative to its size. On the whole, the bike felt a little cheap and plastic. That's the bad stuff.
The good? The bike feels very light, almost to the point of skittish, and the engine is very snappy in Sport mode. It didn't take long to get good confidence in the bike and start to attack corners more aggressively. Although for a £10k bike that's sold as offering the capability to tour I wouldn't want to travel a long distance on one any more than I would my current Aprilia.
Next up was the Multistrada. This is the biggest bike I've ever ridden, so my thoughts are likely to be not as balanced as others. You certainly notice the size, especially the width, but on the move the bike is very light and well balanced. It only takes a little push with either feet or hands and the bike follows well. There's a lot more wind protection than the Hyperstrada and it was altogether more comfortable as you'd expect from a bigger bike. I could ride with my visor up slightly and get a good breeze without a diet of insects.
Even in Sport mode, the bike didn't really feel like it had 150 bhp, and I put that down to it's size. It was certainly pretty rapid, and on the ride there really wasn't any opportunity to really test it out to the full without breaking a host of speed limits. Setting the engine mapping to touring made a noticeable difference, with a far more linear power delivery.
The active suspension seemed excellent - certainly very comfortable - and the ABS brakes, bearing in mind the size of the bike, were composed and could stop it very quickly. Unlike my Aprilia, the rear brake actually seems to work too
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Overall, I absolutely loved the Multistrada. Whether it really is 4 bikes in 1 I've no idea from the ride I took, but I could easily see myself clocking up a few hundred miles in a day if need be, and then having a bit of fun at the destination the next day without feeling cramped from the journey or without feeling underpowered.
I'll set up a ride on the BMW in the next couple of weekends, and then decide if I've learned enough or if I need to try another different bike.