tj,
If you monitor your own pool water and understand the relationship between FC (chlorine) and the CYA (Stabilizer) then using an in-line chlorinator is ok.. The only downside is that CYA does not go away, so when the CYA gets too high, you will have to drain, at least some of your pool water, and refill.
We are assuming that the type of in-line chlorinator we are talking about is to 3" chlorinated tabs or "pucks"... If what your pool builder is calling an in-line chlorinator is actually a Saltwater Chlorine Generator, then that is a whole different animal... and a great thing to have...
One of the reasons that most people come to this site is because they let the CYA build up in their pools over time. When this happens you almost can't put enough chlorine in the pool to keep it from turning green.
When using pucks for chlorinating your pool, you normally have to add packets of "shock" to your pool once a week.
When using pucks for chlorinating your pool, your pool with often smell like Chlorine, the same smell as a public pool.
When using pucks for chlorinating your pool, you have to spend half your life in the dreaded Pool $tore... Buying things you don't need.
Thanks,
Jim R.