Since your priorities are comfort and luxury we would recommend the Tata Safari. The interiors have a more luxurious feel and space and comfort is very good. The front seats are large and comfy and as is the second row too.
Since you are specifically looking for a 7 seater we assume the third row seats would be important as well and here the Safari pips the Mahindra XUV 7XO with a slightly better third row. Access to it is straightforward via the flip-down seat and once back there, knee room is fairly good and you can slide the second row forward to adjust space between both rows. Third row passengers also get a set of dedicated AC vents with their own blower controls.