What effect is tilting going to have on a load that's liquid or granular?
It'll be less inclined to slosh about, as the tilt will naturally keep the centri-whatever
[1] force pointing towards the bottom of the load bed. Just like a bicycle does, and a Virgin train doesn't.
That's the advantage of a tilting trike - less inclined to tip over!
I haven't ridden a trike since I was about 5, which I guess is fairly typical, and can't really grok how any of it handles now. If it were a regular, upright, delta trike, then I'd know I was relearning something, if it were a tadpole I'd be wondering if it would handle in the same way as a delta, but if it were leaning then the bike-like-ness might be helpful or might totally double-cross-disconnect-confuse me.
A trike (delta or tadpole) handles the way you think it will handle - turn the bars, it goes in that direction. The problem with people who've only ridden bicycles since they were a child is that they're used to the more complex process of countersteering and leaning, and it takes a while to override than instinct and make an upright trike go in the right direction. I've yet to re-acquire the skill, in spite of being fluent in both upright and recumbent bicycles, and recumbent trikes.
A tilting trike steers and balances like a bicycle. D-Tek had a drop-in replacement for a bicycle front wheel (turning it into a tilting tadpole trike) on the stall at Mildenhall this summer. I had a go, and it was completely intuitive to ride as a bicycle (the steering was 'heavy', a bit like you'd expect from a combination of big soft tyre and front panniers, only without the rolling resistance), and the stability under heavy braking (on damp grass!) was astounding.
[1] Not starting that debate. 
