At present day I would not rate one rifle over the other, they're both excellent quality rifles and top rate shooters.

I think for the most part the quailty is about the same. The action castings come from the same place. I think that C.Sharps is using Green Mountain barrels these days but don't take that as gospel. Shiloh makes their own. Shiloh may offer more custom features than C Sharps. 
I honestly don't think you would go wrong with either. 
Sam

When I was thinking about a big side hammer long time ago went to both . Shilo was impossible to deal with. Long waits while speculators had plenty of ill suited rifles for sale. Never once answered a letter. At the time most were Crescent butt plates in calibers way too big to be stocked that way.

C Sharps on the other hand was responsive,  answered my letters right away and would make about anything I wanted.

Has Shilo changed ? Will they build a rifle for shooters with a reasonable lead time instead of for dealer-resellers in Quigley configuration 

Boats

I've had a C. Sharps (1875) and have a Shiloh (1874).  Both are fine and the workmanship varies from both manufacturers. Price matters!  What upgrades will you ask for?  I have not shot the Shiloh in some years, but the finish is astounding. I don't know if the wood grows out of the metal, but it sure fits. And it's beautiful. I paid for the wood and some extra fitting and finish. Was not short changed. Had I ordered it the way I wanted it from C. Sharps, I would have expected to be equally satisfied. These beautiful rifles have peaked.  I expect you'd do better to watch the used market and find an exceptional firearm at less than new cost.  Between these two manufacturers, there is no wrong choice.

C.Sharps has many more rifles available than just the 1874 Sharps.

Terry

I have a number of each.  Although I prefer the highwall action, if going with an out of the box rifle I'd choose Shiloh over C. Sharps every time for a competition rifle.

I think the good people at Shiloh take more care when chambering their rifles.   My earlier C. Sharps rifles have been hit or miss with respect to chambers.  A couple of them have been cut with overly long and overly fat chambers.   My best shooting C. Sharps rifles have custom chambers.  I like those ones just fine. 

Chris.

If you want a specific chamber and be absolutely sure it is true on the bore, get your own reamer and chamber it yourself.  A finish reamer will make several chambers before you wear it out by not having a rougher too.