Sale is about to end, what should I get? Metal gear or mad max

Look for Mad Max on steamgifts, will be cheaper.

Since metal gear is only $2 more ex than mad max in india, I suggest you go for metal gear.

Get Mad Max if you enjoy that type of game, i.e running around doing a lot errands like in Far Cry, Assassin's Creed etc. MG will get cheaper and by then you can watch a lot of vids about the MG lore. Which is a lot and can be confusing.
Edit: That's if the absolute price is lower than MG, not just the discount.

Was on the fence about Mad Max aswell, then i watched a gameplay video and immediately went to "another borderlands? nope nope nope".

Snake > Max

Both can entertain you for hours.

MGS V : If you want to drown yourself in its script then you need the previous episodes too. If you want to see it as just an open world game with a decent gameplay and interesting political story then this episode is enough.

Mad max : You can enjoy its gameplay for hours [ 10-20-30 hours ].

I prefer Mad Max, but it's understandable why people would choose MGSV over it.
Personally I like them both quite equally, just that I'm leaning sliiiiightly towards Max.

Want a pirate's suggestion? Mad Max doesn't have Denuvo ^^

In MGS V, you can add in a song track when Pequod, the pilot of your transport heli, flies to you.