We were on Explora in October and loved the cruise, in fact we booked another cruise while on board. I am sitting on the Crystal Serenity now and am also loving this cruise.
They are totally different. Last night we watched a production show with 12 cast members and 6 or 7 band members. There must have been 15 to 20 costume changes, the show was fantastic. With the amount of money Crystal spent on this production I think that it will be around for a while, and the second or third or fourth time I see it I might not be quite as impressed.
That's not to say we didn't enjoy the entertainment on Explora, it was very different but more likely to change. I agree that they need a stronger CD on Explora, when we were on, the timing of the performances was horrible with big gaps where nothing was happening. I enjoyed the lecturers on both ships equally.
When it comes to food Explora wins hands down, and this is a comparison with a cruise line known for their food. I keep watching for complaints about service on Explora and so far have not seen any. I was worried that as the ship was loaded with passengers there would be a problem accomodating them, especially in the Marketplace. This doesn't seem to be the case.
Explora has a different concept and they are going through a learning curve, no dispute, however we totally enjoyed our cruise.