I haven't compared the 2 side-by-sde. However I was told (correct me if I'm wrong) that with Myth the EPG guide data comes from an external source (Data Direct) and with VDR it comes over the air.
My understanding is the Myth/DataDirect data is far more rich--you have actors, genres, detailed synopsis, etc. However it requires registering with an external source and there's a risk it may not be always in sync with the actual broadcast. VDR's guide data is always accurate and doesn't require registration since it is decoded from the OTA broadcast, but doesn't have nearly as much meta-data as the Myth/DataDirect.
Have you tried both? Is my understanding correct? If so, it would seem an ideal solution would be a hybrid: get the EPG data OTA and if the user has a data direct subscription, use it to enhange the ota epg with all the meta data.
This thread seems to have gone off topic a little... but here's our view on the issue of EPG data;
Here in Europe DVB-T, DVB-S and DVB-C are the digital TV standard - like GSM or 3G are the standard for mobile phones. So receiving OTA EPG data is what end users expect. So that has to be there as a base line to support user/customer expectations. However augmenting that EPG data with 'richer' listing Meta data about programs from a supplementary provider is something we see as very important as an added value to the end user. We imagine this will be achieved by taking the OTA EPG data and the supplementary programming data into Mysql and relating the two datasets.
Maintaining the users experience of DVB and then taking that experience to a new level is what we are striving for.