There are lots of options here are some of my thoughts on the choices having flown with all of the types of handles except for two of them.
1) handle with lines and trigger & toggles - these don't work for me because you only can use 3 fingers to hang on and with larger models I like to have all four fingers with a tight grip on the handle. and when you reach up to flip the toggle you jiggle the handle just a little bit and the model is not flying level simply because you touched the handle.
2) RC car transmitter in left hand - this where you fly with your right hand and operate the rc car transmitter trigger with your left hand
3) RC transmitter with neck strap - the transmitter hangs on with a neck strap at your stomach, put Velcro on the bottom of the transmitter and your shirt and it won't move. operate the throttle stick and toggle switches by feel, not by looking at the transmitter
4) Use transmitter tray - this is a tray that holds the transmitter at your belly, the tray hangs on our shoulders. these trays were designed for RC pilots, might take some looking around to find one of these
5) Belt clip - Make a simple belt clip to hold the transmitter on your belt. Again do it by feel.
The last 4 options use a normal CL stunt handle, actually any handle you want. I like the handle to be as small and as light as possible. I don't want to look at it or touch it otherwise the smooth flight will have a bump in it and will look bad. The dedicated handles with everything built into the handle including the toggle switches and trigger to are too big and clumsy for my tastes.
Over the years I have tried all of these except #3 and #4 but I can understand why they are being used today. I have been using the electronic controls since 1991 and converted to 2.4 Ghz in 2013 but the whole time I have been using the belt clip which is easy to put in my tool box.
Fred