I haven't made enough calls with the V30 to really comment on call quality just yet. However, it's been clear and crisp on the few calls I've taken. My major joy is the consistent data speeds. So far no hiccups on speed and my bars stay at 4 or above.My 7 Plus and my husband’s has that same choppy breaking in and out problem yours has and we have Qualcomm modems running on AT&T Service. I get a light static crackle on my S8+. My AT&T S7 Edge, unlocked S7 were more clear but had an occasional pop or crackle. My HTC 10, bought unlocked, was flawless and held the signal great. I never conducted a speed test on it, though.
Yeah, it feels like Apple devices after the 6s seem to have a lot of issues.