I'm against it but don't let that put you off.
My first encouter was Specialized tubless tyres on mavic x819 tubeless rims and one of the tyres got a puncture that I could not fix - I am even more against using the sealant; also the rims make for a heavy set of wheels. I ended up using inner tubes which negates the tubless concept.
My second encounter, in the last couple of days, was with a pair of tubeless tyres - brand escapes me - but these are so incredibly tight it took me two hours to get them off the rim - I doubt I would have been able to do that on the trail. Of course one could argue that since they were filled with sealant, they would not puncture so would not need to be removed but I believe in sod's law that the one time you go out riding without a spare inner tube, you will puncture. Also they tyres are heavy, much heavier than tyre plus inner so weight is at a disadvantage, and yes, I know tubless allows you to run at lower pressure.