I just cut my dreads for jiujitsu, and i already miss them. Im still up in the air as to whether or not i should have done it. The only cons I experienced when I had them was during rolling, They would get in the way a LOT. If i was in the bottom of side control, it was almost inevitable that their knee would post on them and my head would be pinned to the mat (unless i was ok with yanking/losing a dread). And when I would get caught in a choke, it was MUCH harder to slip my head out. So when it comes to the technical aspect, there was definitely some downfalls.
Other than that.. there was also a LOT of benefits. #1 being all the cool people youll meet. Every day I would have at least one person come up and talk to me about my hair. Or offer to smoke a bowl with me (which is always a bonus if youre into that sort of thing). And as for the cleaning them thing.. Its really no different than having normal hair. (Which if youve studied up on it youve already figured it out). People like to think dreads are dirty because a lot of people who have them are dirty (which is true).. but I always saw it as the same argument people use when they say people who smoke pot are lazy. Sure, theres people who smoke weed that are lazy.. but it isnt because of the weed, its because they are a lazy person who just so happens to smoke. As long as you wash your dreads after you roll every day, theyll be fine. Anywhere that sweat and dirt can get to.. so can shampoo and water. Id recommend Dr. Bronners if youre going to buy one (as opposed to making it yourself).. They have a lot of great ones that leave them super clean, and they smell awesome. (And yet arent overwhelming)