After careful thought, I picked the 4 switch woodgrain for the following reasons:
While I prefer the look of a 6-switch (especially sears), it has a heavier RF shield. Some carts fit too snug, potentially scraping/damaging the labels.
7800 colors look washed out/less vibrant.
5200 adapter just looks wrong, like it doesn't belong but someone jammed it into the 5200 anyway.
Coleco adapter relies on the Coleco's iffy power supply, plus there's a split second delay at power up.
Jr buttons are mushy, they collect dust, and when I find them in the wild, they don't always work (every other system has, so far...)
Vader has soldered chips usually, socketed chips are easier to replace if needed.
Never had INTV/Gemini so can't comment on performance, but scarcity knocks them out of the running.
4 switch woodgrain is easy to find, easy to maintain, and easy to play. Solid colors, solid switches, solid performance.