CDMA/GSM capability is a topic that makes all of my friend’s eyes glaze over so I understand what RW is thinking in this respect. These people, when ordering a phone, would be confused by and option to specify CDMA or GSM when placing an order.
This is further complicated by a difference in their MVNO agreements. One lets them tell us the name of the the host carrier, the other does not.
I would propose a compromise that partially deals with this dilemma. In the phone’s specifications include a carrier technology specification that mentions carriers in a general sense. For example compatible with GSM carriers (AT&T, T-Mobile, etc), compatible with CDMA carriers (Sprint, Verizon, etc.) or compatible with all major carriers. The specification would have a footnote telling the reader that a particular carrier will only accept models certified for use with their service.
This compromise doesn’t solve the ordering problem and as long as RW’s contract with their GSM carrier prohibits them from mentioning that carrier’s name or directing them to that carrier’s coverage map they are stuck with shipping a phone that they think will best serve the ZIP code in which their customer resides. Unfortunately the ZIP code where one lives can have remarkably different coverage from where they work or frequently travel.
I’ve found a few serious flaws in the coverage checker and have had to work around them by cherry picking the ZIP code I apply in the coverage checker immediately prior to ordering a phone. For example, my ZIP gets me a CDMA phone (if ordered from RW) but my GSM phone provides me with better overall coverage than I had when I was on CDMA. My daughter’s ZIP shows no cell service at all but that ZIP does have CDMA roaming coverage and native GSM coverage. Simply stated, it is impossible to create a coverage checker that knows the real world situation their customer deals with.