I took a look at both. With battery, Asus TUF M4 Wireless will be around 89g while Razer Death Adder V2 x hyperspeed is about 100g. Pretty heavy if you are looking for a lighter mouse.
Razer claims 235 hr on 1 battery while Asus claims 134 hours on AA battery with 2.4 Ghz. So battery wise, Razer seems to be better.
Also TUF is ambidextrous while Razer's only right-handed.
Both Asus and Razer have pretty bad reputation when it comes to peripherals though....
Whistle-blower, ex-Asus employee claims
ASUS out of touch with current market.
While Razer stuff aren't built to last, a lot of complains from customers.
If I am forced to make a choice, go with Razer. Use an AAA battery to bring weight down to 85g. Last as long as Asus's mice on AA battery and similar weight.