Ive had mine done for 10 years (this month! happy "anniversary" to me??? hrm)
I had the swelling completely down in 24 hours due to KFC ice chips (which at the time were PERFECT as they had a little recession that would allow the cube to sit on top of piercing without actually touching it), and fully healed in about 3 weeks. I actually wanted a "thicker" bar then the one I was pierced with so I "stretched" mine to a 10Ga, this was not too painful, and didnt take more than a week to re-heal. I can take my bar out for days on end, and there is 0 resistance when I try to put it back in. This is great as when Im at conferences etc., people dont need to see my piercings!
Another reason people pierce their tongues is because compared with other piercings, it is probably the LEAST painful. Biting my tongue hurt/hurts WAY more than my piercing actually did. To me it was more discomfort and less actual pain in any case. Also, with very low maintanence, and quick healing time, it is perhaps the mildest piercing for "beginners". My biggest reason at the time was that I really wanted another piercing without having a visible one on my face. That left tongue, nipples, belly, genitals, and at age 16 with no love of the belly button rings...the choice was easy!