Where is this 'on the fly' switch in Plextools you speak of, BTW? Are you using plextools pro? Or is this some kind of feature in XL I'm not aware of? All DAE in Pro AFAIK is 'on the fly'; there's not an option to encue files for encoding like EAC can... more information please...
AFAIK Plextools Pro doesn't have a "File Compare" option (i.e. for two extracted supposedly identical WAV files). Comparing 2 extracted files seems more logical to me than comparing an extracted file to the "original CD", becaue the whole point of the test in the first place is that you may not come up with the same data each time you read from the disk. Certain programs like EAC and AudioGrabber have file compare features which have their own strengths and weaknesses... sometimes not seeming too helpful, except to simply determine IF there are differences, not exactly how much difference there is. In which case, just comparing the number of actual bits in the file seems to make just as much sense sometimes, using 'file properties' in File Manager.
If you use EAC to rip to WAV, you can use the 'Test & Copy' function which reads each track twice and produces a checksum for both and displays them, (so you can later re-rip that track for another try at bit accuracy if you want). If a CD file is damaged and you're not getting an accurate rip, chances are very high the extracted data will be different each time, and that is the fundamental principle behind this process. But even test and copy will not show exactly how much difference there is (i.e. whether the difference is audible or not). But it will give you a warning sign. If the checksums match, your file is okay.
But to answer your question, (AFAIK) XL is the only one which has any kind of comparo, and that in itself is a very new feature. Heck, we can't even use LAME the way it was intended, with full command line switches. I'd certainly hope Plextor would add that before doing some file compare features in a senseless and way overpriced pay-upgrade software, but they didn't. (Directing this at Plextor, not at you personally, of course) Really-----what is likely to make Plextor more money? Adding full command line switch capability to LAME DAE, or spending their resources adding a file compare option to XL, hoping to lure in more new customers [lol]? Oh--too late. But there I go again with my common sense. Seriously though, a file compare option in Pro would be nice. But I think there are some higher priorities which they may or not be in the process of fulfilling (as of now there hasn't even been a release of v2.24c to correct the continuing ABR bugs).
Not to detract from your question, but when using Plextools, a file compare option is not so important because Plextools DAE on a plextor drive is so great (which is why it bugs this community that its LAME qualifications are so, well, 'lame'). Plextools can and should be set to automatically slow down on errors, so re-ripping at a lower speed is moot. If Plextools with a Plextor drive can't extract it, you won't find anything superior IMO, at least anything which will extract the file in a reasonable amount of time (EAC could take hours and hours).