We are happy with the master berth in our Gemini.  It is a queen size mattress which is very comfortable.  We have a TV with a built-in DVD player with external speakers and a Roku Ultra.  We mostly stream with the Roku Ultra through a WiFi hotspot.  We keep the window cover on the outside most of the time since we like it to stay dark until we are ready to get up.

When we first received the boat, it had what was consider the state-of-the-art setup with the original pad with a memory foam pad on top of that.  Comfort was pretty good but making the bed and keeping it all together was a daily wrestling match.  Getting it all together was tough enough but the parts all seemed to slide independently.  This usually resulting in overhang on the outside and a hollow in a corner.

Original pad with memory foam (these have been replaced).
There was even a no-slide layer underneath but it wasn't enough.

In 2014, we bought a 5" Tuft & Needle mattress which has made this our most comfortable place to sleep.  We like a firm mattress and the solid surface with this mattress works perfectly for us.  

5" Tuft & Needle mattress

This has eliminated the sliding and other issues.  Unfortunately, Tuft & Needle stopped offering the 5" version soon after we had made our purchase so we can only recommend a 5" queen mattress for the master berth as a great size but not a specific one.