Sprint definitely needs it in NYC. I roam a lot. Look on Sensorly, which Sprint uses as reference, there are quite a few areas that are low in signal. Including in but not limited to Manhattan, without mentioning towers with signal but no service all over the city.
I personally one of Sprint's numerous mistakes in the past was in not prioritizing the tops markets. T-Mobile is not great outside of cities to this day, but few of it's customers know that.
On the same note
People pay for cell phones and service on other carriers for a reason.
If it is really important to you or anybody else Sprint, under normal circumstances, is not the best choice. On that note, I have a S9+ from Samsung which I configured to use "Calling Plus". It is a nice feature to have when I am not roaming in NYC, as I often do. I have been able to try T-Mobile roaming, and it works very well. I look forward to it being more wide spread.
I had the same issue. I ended up contacting Sprint on Twitter. We exchanged a couple of DMs and then Sprint moved to a trouble shooter on the web and finally had a trouble shooter call me. After some time troubleshooting remotely, they decided to replace the unit.
The replacement unit works well. See the SCP shots before and after in my home taken with a Galaxy S9..
Additional comments: While the MB is not up against a window as recommended, I can get a MB signal on the public street in front of my home. Makes my remote garage door opener on my phone more dependable. Same for my Nest connection on my phone.
I see a difference on both my HTC One M8 and my new Galaxy S9.
HTC One m8 Speedtest in house WiFi verses Magic Box. Not sure how these numbers compare to the norm around here. A moment later, Sprint beat my WiFi upload at 5.12 MbPs.