Is generic (levothyroxine) instead of Synthroid not as good?

Consistency of med. There is no problem with generic thyroid as long as you have some underlying thyroid function. If you have no thyroid function (i.e. After total thyroidectomy), your thyroid level will fluctuate if you get different brands of thyroid or generics from different companies. The advantage of taking a particular brand is that the amount of medicine is consistent so thyroid levels will not fluctuate.
Generic vs.brand. I have no objections to generics. Most of my patients do just fine. There have been some reports that brand name thyroid supplements perform better than generics, though, in that the dose of the medication is more reliable in brands.