I'd also like to hear an "experts" opinion on steel heat
dissipators versus lava rock.

I suspect it will make little difference in taste with only real
charcoal having the unequalled taste advantage.

Perhaps the drippings burn differently (at a different rate) on a
steel dissipator compared to lava rock, imparting a different
flavour.

(Personally I buy a $200.00 barbecue every 4 years or so and use it
2-3 times a week all year. It would take 24 years for a $1200.00
barbeque to equal that payback)