An Extra 1k EXP is nice and it lasts quite awhile but it shouldn't take more than 30 mins to an hour to make the effect wear off. The Chariot Ring(500 exp, 75% version) is worthless. I would much rather get an extra 1k EXP than 500 if it takes me slightly longer to get it. I used it last night and I think I already have the 1k CP I used to get it back. Well worth the use and I believe someone said you can get it re-enchanted, wondering if it costs loss to do that than buy a new one.
Also you do not have to keep the ring on nor would I encourage you to do so. Its much like a blink band or reraise hairpin. You equip it, wait the 15 second activation period, use the item, and an icon much like the regen icon appears except it says EXP instead of HP. The recast time tho is 16 hours, so you need to wait for the next day to reuse the effect. The experience addition is directly calculated into the chain and I was getting chains for 300+(I think 364 was highest I saw). I think the only downside I could foresee is the level difference in parties increasing, but I doubt that would be a huge problem. Its possible someone could level twice before another gets a single level throwing party distribution off slightly but I don't see that happening much or at all. Probably only in low level parties could this be a significant problem.
I also suggest if you are leveling a job that you dislike more than others that you use it specifically for that job, that is if you plan on leveling more than 1 job in a 16 hour period. 1k EXP everyday for a job you can't stand leveling is better than 1k EXP for a job you do. And if you static, everyone in the party should probably use it to keep same level distribution unless you tend to die and lose experience more often than others.