If considering ROI, FMS hands down. XLRI has its own XL-Maafia (HR network)a is kept equivalent to IIM ABC. However, XLRI Delhi is opening this year which will increase the batch size. So, if you want to enjoy campus life- go to XL otherwise FMS
XLRi is better than FMS in terms of its recognition (brand name), placements, campus life and alumni base etc.
XLRi is considered at part with the IIMs like A, B and C
FMS is a great option but the biggest advantage is the batch size and the ROI (because the fees is very low)
Talking about ROI, no college can beat FMS. But if you want to take brand value into consideration, then XLRI is better than FMS. Also if you are looking for campus life, then XLRI would be a much better choice. I would recommend you to go for XLRI until and unless fees is a big consideration.