any issues in using two base stations

No issues I know of. I believe you can even assign the same sensor(s) to both bases if you'd care to.

ftmackinc,

The only thing that comes to mind is that you shouldn't have those Base Stations next to each other, as they can interfere with each other's communications.

But I should also ask - could you achieve the same effect with just the one Base Station? Entry Sensors can all be set to "Secret Alert", so you can get notifications from them without generating an alarm.
Having all of the sensors under the same system, of course, would be the more economical option.

- Johnny M.
SimpliSafe Home Security

I have interior door sensors, defined to the same base as the exterior door sensors.  I just don't have them active in HOME mode.

Can you use two base stations with the same sensors so you can hear the voice prompts better?

You can, but they shouldn't be too close together or they might interfere with each other.  Also, make sure they are always in the same mode, or you'll get unpleasant behavior.  You only have to have one monitored if you want to save on monitoring costs. .