burgled
all but one bikes gone.
I expect i am insured to buy a new bike.
new MTB is the brain curdler.
wheel size??

I'm heavy - 90k
I ride hard and break road wheels with alarming regularity
less so mtb wheels - 26rs never had another size
not a downhiller
definitely want to ride up without killing myself

It seems to me that 650b is what i should go for?. pros and cons ? tyre availability and price
trail or all mountain??

thoughts callers ?

Geometry first. Colour second. Wheel size last.

Six fiddy bee seems to have killed 26 in mid to high end mtbs.
Your other issue will be hub width...

Yep, depends on your height and what sort of suspension travel you are after - I usually ride a medium frame and wouldn't get anything bigger than 100mm travel in 29er, then I'd switch to 650b

Lots of new tyres are coming out 650b and 29 only, and most of the good treads from 26 are migrating.

Trail or AM is a blurry line you'll have to decide for yourself. But be honest with the buyer about the kind of riding you'll actually do, not what you wish you would / could...

If you can get your hands on Demo bikes, try the different sizes on trails you're used to. Predictable answer, but that at least gets you an idea of what 650b, 650bPlus and 29 all ride like. 650 probably will feel the most familiar given its close proximity to 26", though I was quite surprised how fun the plus tyre bikes were to muck about on (didn't feel any slower uphill than my 29" trailbike either).

Regardless of wheelsize - If you can get wider rims (internal of like 25mm up) stock on the bike, that'll make a difference in terms of supporting tyres better and allowing lower pressures.