Everybody has their own preference as each mask offers a different level of protection and different people will find that certain masks are more comfortable for them than others. Personally I loved my pair of Dye i4s because they are light, don't block out much sound, and were very comfortable for me, but I know plenty of people who don't like them because they have a very low profile meaning your whole forehead is exposed and they don't wrap a long way around the side of your head either, but each player has their own preference.
Essentially you can't really go wrong with masks as long as you stick to a reputable brand and if buying second hand make sure it's in good condition and the lense isn't too old.
Basically any of the following will serve you perfectly well:
VForce Profilers
JT Flex 8
JT Pro Flex
Empire E-Vents
Empire E-Flex
Dye i3
Dye i4
VForce Grills
The best thing to do is just make sure you pick up a decent mask, doesn't matter what it is, and once you're playing with other people with their own kit just see if you can try on various masks if you're not happy with yours until you find something you like better.