Hi Benny,
I wouldn't base my bike choice on what works at Lystie - the right rider can get by with pretty much any bike at Lystie.
2 things I think you need to consider. Where is my riding at now and where do I want it to be?
I have a 29r carbon hardtail (9.5kg) and a 27.5 short / medium travel duallie (11kg). If the trails are running fast I love to take the Stumpjumper 29r out just because it is sooo fast - and to me, flying through twisty single track and testing your skills on flat corners, roots and smaller feature is pretty close to peak adventure. We have plenty of trail at Lystie that suit that bike to a 'T'. It's the sort of bike you can get out and crunch out 30k's averaging somewhere near 20k/hr (ie a competitive XC race bike also).
If I'm riding for fun with a group, don't want to think about my riding too much on that day, feel like speeding through (rather than finessing through) the more technical trails or to cure a hangover I take my Pivot Mach 4 out.
To me the Mach 4 is more than enough bike for Lystie and it gets me through the less extreme stuff at the Youies and Buller with capacity to spare. It's not really slack in the head angle and is no fatty bombar - so it's pretty good up the hills also. I have raced it on more technical courses and in wet conditions just because it is so much more forgiving and I tend to stay on it more so than the the 29r.
So, look at what you currently enjoy doing, if that is bombing down the few flow / down hill trails we have at Lystie (or dare I say, heading to the North) whilst hitting every feature you can find then go for a 27.5 with medium travel (Trail - All Mountain if you want to talk bike styles). If you hope to do a bit of XC racing, explore a few other areas with moderate confidence and still be able to ride the rough stuff when you feel like it look toward a short - medium travel 29r. Going for a 27.5+ tyre size can allow you to swap a short - medium travel bike between racy with 2.1 tyres or all mountain with 3.0 tyres. The traction & control the big bags give you in rough stuff is nuts - just not the fastest bike around when the traction abounds on the twisty single track or high 'G' berms (ie it could get scary at Buxton).
Budget is always a talking point. You can get onto a nice 29r hard tail for 3k and there really isn't as much variance between brands (if you choose a hard tail we could further discuss what to look for). I would be looking in the 5k+ range for duallie that hasn't compromised too much on frame materials or the group set spec (ie good fork/shock/wheels/rear mech).
If I was looking at 1 bike to do all I would have a good look at the Trek Fuel EX, the Norco Fluid, the Giant Trance or Scott Spark in the more affordable product range. If you are happy to spend a bit more then start with the Specialized Camber and look at the boutique brands like Santa Cruz, Yetti, Pivot and Rocky Mountain. 29' wheels will give you better speed and smooth out the rough stuff, 27.5 will sharpen up the handling and make it a little more forgiving.
CK
