Main ones i would recommend would be Spire loaders and Dye Rotor loaders, both are good, both have pros and cons.
Dye Rotor is popular and is good, no questions asked, it is durable, but what I dont like about it is that it takes few minutes to take it apart unless it brakes down, then you need to take it off and play with out it for few minutes until end of game. It is durable, i have seen few people put on hard hits on dye rotors they are quite durable.
Spire is probably better for less trained people, for those who get more paintballs outside the loader, i mean it has bigger hole where you put your paintballs through. Also you can take it apart in few seconds, it is also durable, yet if you put bigger hit on it the see through plastic back will slide of and you will need to put it back on again, but that is only few second job.
After that we probably come to Halo Too loaders who get smashed quite easily but still work, but need a lot of cleaning after every single time, you will probably need to take all loader apart to clean it.