I am remodeling contractor and I NEVER buy silicone caulk.
It only advantage is high resistance to mildew, but what good it does when adhesion is very bad?
Also very messy in application, as we can read above.
You want good exterior could - buy cheap neoprene caulk, or spend money on high tech caulks.
Lately run at HD into clear roofing caulk. No long-term experience yet, but so far so good and clear sure make it pretty universal.
More about eternabond - PO damaged the camper and instead of repairing holes in roof and siding - glued everything with tape.
The only purpose the tape did was cover-up and holding the water so the frame rotten faster.