If you plan on purchasing an Astron RS-35M Linear like I did, plan on the meter lamps and very possibly the meters going dead after one year. You cannot just change out the lamp. They are enclosed within the meters and Astron wants you to buy a new meter or meters!
You can change them. I have changed them in an Ameritron AL-811A where the bulbs are in the meters. You have to be careful but it is not that tough to do.
I had an Astron RS20M I used from 1995 until this summer. It didn't have any lamps in the meters but I never had any problems with it. The lamp in the switch still worked. I came across a very good deal on an RS70A so use that now.
The meters don't do a whole lot for you. I don't miss them. I hardly ever looked at them when I had them.