Assuming that for their demo at http://flite-hts-engine.sp.nitech.ac.jp/ they would select a good data set and parameters, I have to say that I'm not particularly impressed. Do you know of any online examples of a well-tuned Festival set up? I didn't find the 'official' Festival or Festvox examples especially great, certainly worse than online available TTS services, and I have never been able to find an example of a well-tuned result of Festival.
I don't know of any online examples, sorry. The problem is that a well-aligned festival voice is not academically interesting, so people generally don't publish it. Festival performs well when it can rely solely on unit selection and has multiple choices of the same phoneme sequence. Once it has to do some guessing on the synthesis, you'll see a drop in quality.
With a small bit of work, you can have festival use an HTS voice directly. I usually use festival to generate my label files, post filter the phoneme timing, synthesize with HTS, then apply a post-filter.
Flite is not Festival. It is a very cut down version for embedded machines.
Flite lacks entonation on questions and such.
It will work better on the ZipitZ2 and pentium2 machines.
Enough to listen short stories, but it's not suited to listen a full book from you bed.
Yes I know, but the GP commented on both Flite and Festival, and I addressed both comments - albeit, I'll admit, in a tangled way.
Festival can produce very good results, but you have to get into the weeds with it and do a lot of planning. If you don't like Scheme, you're not going to like dealing with festival, and if you do like scheme, you're going to be frustrated by their particular scheme.
I've also noticed a lot of folks looking at post filtering, but that is a sea of dragons at the moment.