Sumos/Timbrens are set and forget, and have a life-time warranty. Air bags are an active system, and if you want finger tip control, it will require an
on-board compressor and a 4 way control panel, which is more expensive. The install is also more complicated. There could also be more maintenance, as the air lines could be damaged, or just age out, and need replacement. The compressor could also give problems, but most are pretty robust now. I do not believe the air bags have a life time warranty, but I could be wrong.
Its your choice, you know the saying, "pay me now, or pay me later".