I know all the new 4G phones have GSM radios, but I heard that many (or maybe even all) of Verizon's smartphones make it so certain capabilities - specifically, data - don't work with international carriers, even if the phone is unlocked. Are there any smartphones (other than the iPhone) that would work as if it hadn't been tied to Verizon originally? I'm due for an upgrade and I'm planning to spend a lot of time in Israel.
You're going to have to dig really deep into the specs of the phone to answer your question.
The issue is not the features themselves but the frequency spectrum on which these features are available.
You can look at:
to see what is typically available in Israel. From experience: IPhone 4S from AT&T works like a charm in Israel for both Data and Voice. As far as I know GSM Voice Frequencies used in Israel are: 800(old, possibly decommissioned), 900, 1800, which IPhone and most Androids support. The rest you will have to find out.
Now if you wanted to use CDMA, like Verizon does in Israel, roaming doesn't work on Cellcom's network as far as last information I have.
Last I checked my Verizon CDMA phone worked in Israel. I was receiving telephone calls on my New York number. (Ouch that's expensive!)
Telecom is a GSM provider.
Pelephone was and may still be a CDMA provider