Tabasco is the only pepper I pick unripe, and I grab it at its yellowish-green stage instead of the later orange or red-ripe stage. Four reasons:
-They have a sharp, powerful--too powerful, IMO--taste while red and ripe. The riper they get, the stronger this is. They are best somewhere around the end of their green stage and progressively get worse as they turn past orange.
-They have a nice, steady burn while still young. I've ate some red ones that were some serious firebombs, but it's a quick heat that just dissipates too fast. The less ripe ones seem to have a more lasting effect.
-They take FOREVER to ripen. Seriously, I get hardly any fully red-ripe peppers off these things. It's a waste to try. These peppers just don't seem to want to ripen in my climate... they seem to be more suited to climates closer to the equator. I've rarely had major problems with peppers ripening so far, but when I do, it's always tabasco. So I give up on letting them ripen.
-Once fully red and ripe, they quickly turn the mush. They just don't seem to last, and with the time required to get them to this stage... it just seems pointless to ripen them fully.
Jalapenos, Scotch bonnets, habaneros, other C. chinenses, C. baccatums, Rocotos... I let them all fully ripen so far with no problems. Some ripen slower than others, but I've yet to see such poor ripening times as the tabasco. I even typically leave them on the plant for up to a whole week to make sure they're as ripe as possible (yes, at the expense of heat; a small number of capsaicinoids converted to sugar is not a bad thing to me).
The way I see it... the riper, the better. Usually. The fully-developed sweetness and overall flavor is important to me... not just the searing heat.