Heil seems to be the only brand in the catalogs
Their are many others besides Heil that work great but you will have to shop around. MXL, Shure, and others make good studio mics. I know a lot of people using MXL mic's and they sound great. You would probably have to look somewhere besides the ham catalogs to find brands other than Heil. Musicians friend and B & H Photo are a couple of places that sell a lot of audio gear and various studio mic's. Some studio mics will require 48vdc that your rig probably won't supply so be aware of that. You would have to supply the voltage from another source. Fortunately the PR-781 is not one of these.
I currently use a Heil studio mic with the Pl-2T and love it. However, price is not everything. Their are a lot of mics out there for half the price of the Heil's that sound every bit as good. You will just have to experiment and figure out what works for you. I don't think you will go wrong with the PR-781 though.
How is T/R switching handled? I definitely want a locking transmit button/switch within easy reach (not the transmit button on the rig).
As for T/R. The Heil cable has a pigtail with a 1/4" mono plug. I have the Heil HS-2 hand switch and it is very comfortable and easy to key. No locking feature but I haven't found it to be too much of an issue when keying for long periods of time as the key switch is pretty light to the touch.