Getting the most from any particular choice depends on using it in the correct location with the correct application technique. Here are the strengths and weaknesses of some of my favourite caulking choices. Nowadays silicone is still an excellent choice, but it has been given a run for its money by a few high-performance competitors. Just the same, silicone is still hard to beat when it comes to retaining long-term flexibility, resistance to shrinkage while curing, and the wide temperature range it can be applied in. I've successfully laid beads of caulking in 35C heat and -20C cold.
Silicone is also highly resistant to heat after it has cured.
I've used ordinary formulations to patch the muffler on my truck and find that it lasts much longer than the brittle muffler cement I'd been using before. The best grades of silicone have a 50 year warranty, though probably not as a muffler sealant. For one thing, it's more expensive than other choices, and it's completely unpaintable. All kinds of finishes simply bead up on hardened silicone caulking. Also, silicone isn't particularly easy to apply.