No brainer. XLR should be equivalent sounding but in addition XLR negates a whole host of ground loop and other issues - so performance will always be at least as good but can often be better in many instances.
Should I upgrade to XLR interconnects?
I recently purchased a Marantz SA-11S3 SACD player to pair with my Marantz PM-11S3 integrated amp. The SA-11S3 has balanced outs and the PM-11S3 has balanced ins. Currently I am using RCA interconnects. Is there any benefit to upgrading to balanced for these particular units? I do not want to drop big bucks on new cables if the benefits are minimal.