Difficult as the A10 is one of a kind, however I would go for the Jaguar. The A10 can only operate where the US have control of the air which to be fair the US has always had. The speed of the A10 would limit it in any other situation.
The Jaguar has fought wherever the RAF has fought and has never lost one to enemy fire (ground or air to air). The Indian Airforce has also used them and I don't think they have ever lost one to enemy fire as have the French who I think lost a couple in the first Gulf War. This must be close to a unique record for a GA plane, as most people recognise that GA is a very dangerous business.
There have been a number of stories over the years which will never be proved that Jaguars were used in the cold war for sorties across into East Germany and other soviet satellite states, again without loss.
The RAF planes on board sensors were well ahead of those carried on the A10 when it first came into service and it had a reputation for accuracy in bomb delivery that was second to none. Even the Nigerian Air Force won some bombing contests in the late 70's using the Jaguar, which is saying something. Did I hear someone say ex-pat pilots.
Clearly the Jaguar doesn't have a Gun like the A10 nor could it take the sort of battle damage that the A10 can.
For the first point the Aden wouldn't knock out a MBT but would have a better than average change of knocking out an APC.
For the second point, at the end of the day, none have been lost so it obviously has something going for it, even if its just more difficult to hit.
The A10 is an excellent aircraft but if I had to chose one for my airforce, it would be the Jaguar. It would give me more flexibility and options.
Its worth pointing out that the Indian Air Force who could choose almost any aircraft chose the Jaguar over everything for long range GA and are still building some under license. Its also worth mentioning that the first none US aircraft to take part in Red Flag exercises in Nevada were Jaguars and none were claimed by the defending forces (ground or air) until the fourth day, which is going some.