My personal thoughts on this:
I currently have four handheld remotes -- two for DCS and two for Legacy/TMCC. For now, they are fine.
But I can take a hint. The future is screen control of both systems. Roger at Trainworx has one working in the shop, and the next time I go to the metroplex I'll test-drive one and see how I like it.
In the early 2000's, the railroad furnished me a Blackberry phone. I hated it. So, when I retired on the last day of 2007, I got the most basic flip-phone. That was fine until our six children began getting iPhones and wanting to connect with us in ways other than voice phone calls. So, I reluctantly got an iPhone, and was surprised that I did not hate it. I am not on it all the time, but I have found it to be quite useful in many ways. I will probably buy the interfaces for both systems and use the phone to iPad (yes, I gave in and got one of those too) to control the trains.
I like for the trains to run realistically, slow starts and stops, sometimes complicated maneuvers to get to and from the yard and engine facility, etc. That will probably work well with screen-control. Currently I control my switches with DCS and it takes a lot of time to leave train control and go to switch control, dial up the switch number, activate the switch, and then go back to train control. As an Engineer in the 1970's, I waited for Switchmen to stroll up to the switch, line it, and then give me a signal to move. I don't really want quite that much realism. 
