For me, Panel is a bit like a rock when I want to hammer in a nail. It works, but it isn't the best solution, and there are definite downsides. A hammer will always work better.
I was really hopeful that Panel, as an HTML5 application (I believe it is?), would become a whole lot more than it is. I was, and still am, looking for a fully user configurable thin client that can operate on a multitude of devices. Preferably in a browser on a TV being one of the supported options. I was expecting to be able to configure Panel via the server, much like configuring Theatre View via Standard View, and then simply launch it on a device with my configuration. I was hopeful of an interface much closer to Theatre View than it is.
I use it occasionally on my Android phone, to control my HTPC. But I usually use Gizmo to do that task, and it does it a lot better. I can use Gizmo as a direct Remote Control. I use Gizmo when outside my home network, to play content, or look up what I have at home.
The search function in Panel is just annoying. I drill down through Video to Shows, and search for "Doctor", and get all media types back in a list; Audio, Video, Images, etc. There is no context search. There is no search refinement. Pretty much everything is a big dumb list. The Gizmo search isn't much better, but I am more used to the results, and I can see more information in the resulting list. Unless I recognise the name returned by Panel, and it can be just an Episode or Track name, I can't even tell what sort of media the result is. I have to play it to be able to tell. How silly is that?
I was very disappointed when you decide to use Panel as the front end for Android version of JRiver, even in the short term. That is a good part of the reason I haven't downloaded Android version of JRiver yet. Sure, there is also the very limited and new functionality, but if it is just a Panel front end on a MC server running on my phone, what advantage is it giving me? Particularly while it is only able to play media from the default location on my phone, and not from my 200GB microSDXC card.
I still have hope that you might see Panel as becoming a whole lot more. It has no doubt been a learning exercise. I would like to see that learning leveraged into a fully fledged, fully configurable, thin client front end that will run virtually anywhere, connected to a backend MC Server.
Today, Panel looks and functions like a small app written by a one-man software development company, and we know that can be done better, as JRemote exists (even if I don't use it, because of reported issues with the Android version).