The only musket caps I've shot were on reproduction rifled muskets so I can't say whether they are better than regular #11s on a regular rifle.
A first thought is they should be better but then there is the issue of size.
Musket caps are larger in diameter and some of the regular rifles hammers aren't very large. Any mis-alignment of the hammer with the nipple could make the hammer hang up on the larger caps. That would make things worse.
IMO, the best solution to making a percussion reliable deals with the loading methods more than the size of the cap being used.
Of course everyone knows they should "pop a few caps" on their gun before loading just to blow out any dirt, oil, spiders etc that may be in the gun.
Most know that they should run a clean patch down the bore to wipe out any excess oil that may have run down the barrel and collected on the breech plug face before loading the first shot too.
What some folks don't know is when they load, the hammer needs to be at half cock with no primer on the nipple.
After dumping the powder charge down the barrel, its a good idea to rap the side of the gun with their hand, somewhere down around the breech of the barrel. This will knock some of the powder down towards the nipple.
If they load this way, when the ball is rammed down the bore, the air under it will blow the powder back under the nipple so the slightest flame from the cap will set it off.
As for brand names, I've had my best luck with the #11 CCI Magnum and the RWS caps. These seem to have the hottest loudest flame.
I would rate the Remington caps third, but that is just my opinion. :grin:
zonie