I find slayer to be enjoyable and a decent moneymaker. I like training combat through slayer because I don't get bored training on the same thing constantly, tasks are level appropriate, and I get some good drops, lots of charms, and a ton of clue scrolls. Slayer is further great because of the new points system. It makes you nice money if you trade points for slayer dart runes, especially now that pvp has been released. So if you factor in clue rewards (which can be worth over 12m if you get lucky), monster drops, and swapping points for runes slayer can make some pretty sweet cash. If you want to talk charms, it depends on the task. At waterfiends you can get well over 70 crimson charms per hour. More like 100.