I am an reserve ACISS (Sig Op). I love my job, my other occupation is a student the reserves is what I look forward to every weekend.
I have been in for a little over two years now. Before we begin I have never worked with the Artillery so I have no idea how they work. I only have one close friend in the Artillery world and he barelys shows up

so I have no information to pass on the trade.
I have no idea how your brigade works or how many other units your supports but at my unit we are pretty busy. So as always with the military your mileage may vary. What Brasidas said though is good advice and once you have some questions to ask based on what you read here/elsewhere go in and ask.
The good about the trade.
We are able to be attached to pretty much everything. (Engineers, Infantry, Arty, Service). So there is a variety of different jobs. One weekend you might find yourself working in a heated CP other weekends you might be running around with the infantry.
It is has a hands on technical job at times it can be very fast paced which is also good.
The bad
If something goes wrong with comms it is "always" the sigs fault. This is a little frustrating but it is what is.
Physical Demand
It depends what your doing for the weekend. You might be running around with the infantry or you might be sitting in the back of the truck. But we also generally are driven most places until we get detached. Stay in the best shape and pack light just in case.
Bottom line
Sigs is a good go IMO, I'd recommend it to anyone. It is hands on technical job, sometimes it is quite challenging as there is lots of trouble shooting involved. There is a lot of information you are required to know, if you don't know it all (Trust me there is a lot) bring cheat sheets to the field. There is a variety of different jobs you will be doing which keeps it interesting. There is also options to specialize within your
trade depending on your unit. You may be able to become a lineman or do IT if you desire, it just depends how your unit operates.