If the maker of the software says all are compatible, then what do you mean with "best compatible"? For me, compatibility is a black or white questoion, not something with grey's in between.
I want to buy a GSM modem for using OZEKI NG.
According to this page, Sierra, Huawei and Wavecom modems can be used with this SMS gateway.
Can you recommend me the best compatible model that is currently available on the market? (Its capacity should be up to 3000-4000 SMS/day.)