The SH4 is a little better than the SH3.
The SH3 had an issue with the internal chipset (intel Puma 6), its was not VM fault, but the way they handled the issue was a disgrace.
My SH4 is running fine in my area.
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Red (VM SH2 AC Beta tester)
Running on 1Gbps VM service with SH4 in Modem Mode, with a ASUS RT-AC5300 router. With this setup I get Fantastic WIRED and WIRELESS Signals in my home. I dont work for VM. But I work in IT, and I know my tech.
My advice is at your own risk. If you are happy with my answers please press Kudo ?