Anyone here try it?  Is it more reliable?

I've never tried it because I've never found any need to, my inlines have never experienced ignition problems because I wasn't using 209 primers. As a matter of fact, some of the empirical evidence suggests that the standard 209 primers might be too hot and have been causing some problems, and that's why there has been the development of the newer, less hot 209's by Winchester.
The originals were being blamed for causing hard crud rings in the breech when used with 777 [esp. pellets], and there are also claims that the extra force of the 209 primers were causing the sabots to move forward off of the powder charge before the powder could fully ignite, a preignition jump so to speak. This could affect accuracy, consistency and maybe even increase pressures.
So, even though the new 209's are suppose to help eliminate reliability problems and deliver better performance, I feel that if the old #11's aren't broken and function reliably, why try to fix a non-existant problem by replacing them.
Plus, I've always been happy with the lower costs of the #11's.  
I've never made achieving higher velocities and long range minute of angle accuracy a priority when it comes to hunting with a muzzle loader. I'm a woods hunter and shots are not usually at long range. I would rather minimize recoil rather than changing to something that might increase it.
Since I don't shoot pre-formed pellets, I actually prefer #11's over 209's, and the inline rifles not requiring their use.  

Thanks, sun.  

The problem is that there is a problem.  With #11 caps I have frequent misfires.  I did some trouble-shooting with another hunter who is very experienced with muzzleloaders and we just couldn't get the Ruger M77/50 specifically to fire reliably.  I've shot two deer with a side-lock and haven't had any misfire issues.  I think this is gun specific.  He had the same problem with his and we got nowhere with Ruger.  

So I bought the musket primer conversion and after some tweeking finally thought I had worked out all the bugs.  Apparently not because I got owned in a big way by a 6-pointer (3-pointer for those on the West Coast).  If the primer is not seated very hard, it needs a second strike.

Anyway, my intention is to buy another muzzleloader but wanted to give the 209 conversion a shot to see if I can salvage this muzzleloader.

If both the original and musket conversion primer systems share a common problem, it sounds like a weakness in the firing pin or striker, or some kind of headspacing issue between the nipple and firing pin.
Did you actually send the gun to Ruger?
Sometimes shimming a nipple can result in a harder strike, but with bolt actions, the tolerances are so close I'm not sure how possible that is.
Lastly, maybe you could have a custom #11 nipple made that's just a little bit longer to obtain a better strike. #11 caps should require a lighter hit to ignite.
There's outfits that make custom nipples, and maybe you can always custom fit the length after you receive it from the maker.

Here's one outfit, and even if you need to send the gun to a gunsmithing expert to resolve, there's people who can help if Ruger can't or won't.

blomquistpercussionworks.com/default.asp

I would keep trying to pursuit the issue with Ruger too!

sun

Quoted: If both the original and musket conversion primer systems share a common problem, it sounds like a weakness in the firing pin or striker, or some kind of headspacing issue between the nipple and firing pin. Did you actually send the gun to Ruger? Sometimes shimming a nipple can result in a harder strike, but with bolt actions, the tolerances are so close I'm not sure how possible that is. Lastly, maybe you could have a custom #11 nipple made that's just a little bit longer to obtain a better strike. #11 caps should require a lighter hit to ignite. There's outfits that make custom nipples, and maybe you can always custom fit the length after you receive it from the maker. Here's one outfit, and even if you need to send the gun to a gunsmithing expert to resolve, there's people who can help if Ruger can't or won't. blomquistpercussionworks.com/default.asp I would keep trying to pursuit the issue with Ruger too!

Ruger was a dead-end.  They've actually discontinued this rifle.

I'm going to take the gunsmith route.  I talked to one today and we're going to try the shotgun primer conversion and change the striker spring.  I'm going to buy a new muzzleloader anyway but I'd still like to get the M77/50 up and running if possible.