The Asus should improve your wireless signal strength, if it will improve your speed, that depends.
First of all, I would check the actual connection speed by connecting a device directly to the hub by ethernet cable. The SH1 is more than capable of 100Mbps whilst wired. If you can get 100Mbps on a wired connection, then you can start looking at the wireless side. If you cannot get 100Mbps wired during peak and off peak times, then posting the hub's power levels and network logs would help.
On the wireless side, first of all I would check the specifications of your wireless devices. 50Mbps is a decent speed on the 2.4 Ghz band, for a single stream wireless device. To get around 100Mbps wirelessly you will multistream MIMO devices, preferably using the 5GHz band. This is where the SH1 really falls down as it cannot broadcast on the 2.4Ghz band and 5Ghz band simultaneously. It also has a poor wireless range as it is completely underpowered. I am suprised VM will not swap out the obsolete SH1 for a SH2 at least.
The Asus will can broadcast on the 2.4Ghz and 5Ghz bands simultaneously.and offers wireless AC as well. You will need AC capable devices to take advantage of the speed benefit AC offers.
Wireless reception is affected by many factors like Range, Client hardware, the Topograpy of your home, and the big killer, Wireless interference. Positioning of the hub is important, it should ideally be placed in a central, open position, away from obstacles and electrical devices.