Right off the top - neither. Mainly because of maintainence and reliability.
Let's say that reliability was not an issue, then for performance, the smart money would be on the Alpha.
These cars are very different from each other in so many ways, that direct comparisons are pointless and mostly irrelevant- in my opinion.
But for the the purposes of a friendly comparison among a bunch of car guys like us here, the choice seems to come down to preferences in design.If that is correct, then the svelte and frisky appearance of the Alfa is more appealing to my eye that the block like design of the Triumph with its tractor based engine and inadequate brakes is a distant 2nd place.