I also used to have my tongue pierced.
For me it did not hurt getting it done, but the throbbing and dull pain and swelling for the next couple of days is not fun.
Also having to rinse your mouth many times a day, and not being able to speak properly, and lisping (lithping

) , and having to eat soft foods, and biting your swollen tongue, and catching (biting) the initial jewellery (longer to cater for tongue swelling) with your teeth, and having to take time off work because you cant speak properly, and learning to eat all over again, and learning how to put a fork in your mouth without hooking the jewellery, and learning how to get spagetti to go down your throat without knotting itself round the jewellery and the other end hanging half way down your throat making you want to retch is also is not so cool. This all goes on or about 10-12 days healing after which you can downsize the jewellery. I downsized to 13mm with a smaller ball on the bottom and this stopped the bruising of the upper and lower palate, and also helped stop the tooth chipping.
Another consideration is the possibility of infection (Subacute bacterial endocarditis (Streptococcus viridans)) of the heart valves if the jewellery is not sterilized properly or removed before it has healed. So you cant just take it out because it is sore, or swollen, or you cant talk or eat etc.
BUT
having said all that, it is a lovely toy once it has healed, you can stick your tongue out at passers by and see the annoyance on their faces, or you can play with it all day, gripping it between your front teeth and pulling your tongue back (until you chip a front tooth), and playing the piano along your molars (until you crack one and it costs a couple of hundred to have it fixed).
So maintenance and upkeep? Not much except for taking it out and giving it a good cleaning each week and of course the dentists bills. Oh and their bills skyrocket and the medical aid won't pay because it's a self inflicted injury.
Sex! It doesnt make too much difference.
Overall Rating/Opinion :- Go for it! Do it! have fun! you only live once!
Would I do it again :- Hell yes! It was fun while it lasted, but this time round, only if i could put it in and take it out when i wanted, and if the hole didnt close up after an hour or two, and neither of these are gonna happen, so No, I won't do it again.
Hope this helps
ps. Its a bit of a long story i know but at least you will have a good idea of what you're getting yourself into.