I have used the Shotmarker (at 600 yds) and Hexta (at 600 and 1000 yds) electronic targets and the Target Vision UHD (at 600 yds).
The Hexta system works well, but is considerably more expensive than the Shotmarker. I believe the Silver Mountain system is more expansive as well.
The Shotmarker is priced reasonably close to the Target Vision and works quite well. It’s software is easier to use than that of the Hexta. I really think the choice comes down to the Shotmarker vs, the Target Vision camera system.
The SM is a true electronic target and will give you score while the TV will only show the bullet holes. I have found using the TV UHD I am able to score the target using the camera and be 95% or more in agreement of some one (or me) looking at the target in the pits. It is very clear when using an IPad Pro as a screen. It is easy to set up and requires no special target frame. You do, however, have to go down range to paste holes. A typical string of 2-5 sighters and20 record shots seems to work out well.
The SM may require a specially made frame as it needs extra stiffness to limit deflection from wind to obtain max accuracy. If you have a little carpentry skill, this not hard to do. If you have transport the frame to the range, it may require a method to fold it or allow for final assembly at the range. The TV requires no special frame, of course.
The SM will require initial calibration so that the acoustic center corresponds to the target center. This is actually an offset and need be done only once.
The SM may require some cable and sensor installation in the field, if they cannot be left in place on the frame due to weather exposure.. The sensors and cables are premade and use RCA plugs and jacks. With practice, the installation can be done in under 10 minutes. There is no need to paste bullet holes with the SM. The target face will require replacement at some point, of course, due to the bullet holes.
Both SM and TV will benefit from the use of a tablet which must be purchased separately. Since it is a camera system, the choice of tablet for the TV is more important.
I hope this helps.