I hated the SM7B for years, now I like it. Tastes change, and without doubt the human voice is more connected to different mics than instruments are by far. An SM7B might suit some voices perfectly, and even help people with gaps in their teeth so they sound a bit cutting - the SM7B tends to be good with sibilant HF. A condenser makes the gappy teeth noise sound horrible. Other people have bassy or trebly voices, and need a sympathetic mic partnership.
One thing - you said XLR to USB? the MV7 has a USB connector and an XLR - XLR to an interface, USB to a computer. The mic sounds like a dynamic and is quite pleasant. If you have the MV7 - what don't you like? You keep hearing it's not the best??? What does yours sound like.
If you want an honest opinion - slap a clip on soundcloud or similar and we will tell you what it sounds like. Typical comments are usually - it sounds fine. That means your voice comes through properly - you don;t sound boom, sibilant or poppy. Some people have great VO voices, others don't. If you want we'll tell you that too - mics great, but your diction is bad, or you're talking through your nose, or youre just too close, too far - but the most common comment is 'your room is bad'. Far more than the mic or the voice is bad.
People who say X mic is rubbish, or Z is so much better rarely live in the real world. There are few awful mics and the Shure is not one of those. A bit pointless swapping it for an SM7B, pre-amp and interface if your mic, via USB works fine.