If I had to make a choice between the two colleges, my decision would have been to go for XLRI-NCR campus. Some strong points that favor my opinion are

• Brand: The brand name of XLRI is very strong and not comparable to the new IIMs. 
• Campus: IIM Udaipur campus is still incomplete whereas XLRI has a permanent campus with world class facilities.
• Pedagogy: The pedagogy is almost similar to that of the original branch of XLRI. This means most electives will be taught by renowned professors from XLRI itself. The pedagogy of IIM Udaipur is nowhere near that of XLRI.
• Placements: The best part of placements here is that the summer and final placements of both the institutes (XLRI Main campus and NCR campus) are held together. This opens doors for top consulting and FMCG companies that do not visit the IIM Udaipur campus. A slight comparison between the placement statistics of the 2 B Schools is given below

I hope the above points are enough to convince you to go for IIM Udaipur.