A bit of background to this;
I tried a mates 800 with a rallye seat and liked it.......a lot. So I paid Barrie Robson in York £350 and they shipped one in from Germany.
I liked the 700 but the distance from arse to footpegs was too small, the Rallye seat is about 3-4" higher than standard so gives waaaay more leg room.
Also because it is flat and does not slope towards the front I think its a lot more comfortable, no constant shuffling back every time you brake or hit a bump. on a decent run I reckon it would be great to be able to move back and forwards rather than being stuck in one position.
Sadly I never got to confirm this because I never rode my bike with the new seat fitted. The bike has gone so the seat is very very surplus to requirements.
I would politely suggest if you are not well endowed in the leg department it may be a stretch. I am a 34" inside leg so I can cope with off camber moments on a Tenere 700 so the F700Gs was like a kids bike to me. YMMV whatever the hell that means.
I was going to waffle on but if you read this far and can put both heels down on a 650/700/800GS twin then this is the seat for you.