I'm ready to start training on rollers again - been a LONG time.

In getting set up to train on the rollers, I want to get a dedicated bike for it that I can keep in the basement. I don't want it to be fancy or expensive or pretty, just solid enough to get the job done as a trainer. I can pick up a decent fixie for a couple hundred bucks, or an older steel roadie. I want it to be low-maintenance, set-it-and-forget-it. A FG/SS is appealing to me for that reason.

The question is, will a FG/SS allow me to train as effectively as a geared bike? Obviously I can hold a steady cadence or speed it up/slow it down within reason, do some HITT within the capabilities of the gearing, etc. If I go this route, will I be missing out on on some training opportunities provided by a geared bike?

Thanks in advance for your thoughts on the matter.