Transreflective screens are quite amazing. Even my non-transreflective 450nit Lilliput 669GL-70NP/C/T/5HB is unreadable in direct sunlight. This is pretty rare, but it does happen.
However, the price for them is just too ridiculous. I just cant justify spending $600 for a 7" touch screen. Compare that to what else you buy with similar money and its just insane. My $200 non-transreflective screen is already overpriced IMO, you can buy a whole laptop for less than that.
Someday maybe these screens will become more mainstream so vendors won't be able to rip us off so much.. just because they can.