I'm in the process of deciding whether to use SSRS or CR for our reporting needs. I have read through several discussions, including Crystal Reports vs. Microsoft SQL Server Reporting Services and Compare SQL Server Reporting Services to Crystal Reports. All very good and valid points.
The over-all consensus seems to be that SSRS is a better bet, especially for web-based reporting (C#, ASP.Net) with multiple export type functionalities.
The only concern that we have had in discussions is that we're not entirely sure about how SSRS will gunk up our SQL Server.
Also, all of data is only accessible by sprocs - no direct table access, and I've read about some of CR's SQL-related issues, which appear to be yet another deterrent.
I just want to ensure that using SSRS on our productions servers will not in any way hinder our current server's performance.
SSRS has a pretty good caching option, so it shouldn't hinder your production server. CR has caching too, but it uses ASP.NET caching (the report data is cached in your web servers worker process and is not something I would recommend).
SSRS has blown CR away in my opinion; I find the SSRS IDE much easier to use than CR, it seems to be a lot easier to deploy, and SSRS offers a lot of options that CR doesn't.
I've used sprocs with both SSRS and CR - I haven't seen any issues with either.