All Robins have a standard skill set, and can all be considered very capable and able to tear apart the usual bad-guy teams with ease, can be considered to carry tech that can enable them to punch above their weight class, can be considered as close to peak human as one can get without being Bruce Wayne, and can be considered to be quite intelligent.
However, each has a specific skill set that they have polished to the nth level:
1. Dick Grayson: By far the most agile Robin. This is not to say that the others are not agile ...all are, and even Jason has been shown dodging bullets with a smile on his face. But Dick is the most agile human this side of Daredevil and Spider-Man;
2. Jason Todd: By far the most brutal. This is not to say that the others are not brutally efficient ...all are, and it’s evident Damien is a little monster and Tim has some ruthless tech. But Jason is the one who doesn’t give a F, wants to hurt people (wants, as opposed to Damien who was just trained that way), and always takes a brutal approach to stuff (eg techy combat blades built into his suit’s gauntlets);
3. Tim Drake: By far the most intelligent. This is not to say that the others are not smart in their own rights ...all are, for example Jason managed to bypass the Batmobile’s security and take off its tires, and Dick has managed to penetrate the freakin’ Bat cave’s defenses. But Tim is the only one who deduced Bruce’s identity, he is the only person (apart from Bruce) that Ras calls ‘detective,’ and is considered one of the smartest people in DC. Batman has even said he may eventually surpass him as a detective. Add to this crazy tech, and Tim is the genius of the Robins.
4. Finally, Damien Wayne. By far the best fighter. This is not to say that the others cannot fight ...all are, and we know Dick can handle himself at the highest levels, Jason is a one-man wrecking ball, and even Tim Drake was trained by Lady Shiva herself! However, Damien was trained in combat from birth ...by the entire League of Assassins (which includes people like Shiva, and unlike some lessons given to Tim by Shiva and some crazy mystic monks, Damien was raised up in that shit). In fact, Bruce’s major task with Damien has been to tone him down! The only thing Bruce can teach Damien in H2H combat is to chill.
What does this mean for the threat?
In a cage fight - unless Dick, Jason and Tim gang up against Damien and take him out, it is Damien that is going to win. While one or two of the others (eg Dick) have managed to handle Damien in a scuffle, in a real no-holds-barred anything goes fight, Damien is the closest in the group to Batgirl. Not at the same level obviously, but I’d put my money on him.