I like my DX6i. Fits my hands nicely, has more options for receivers. For example if I was building a little park foamy, I don't need to spend 70-80 on a rx. I could just get something like the ar6000 for around $40.

The DX6i also has a larger menu screen and is easy to program (not many abbreviations). It uses Four regular AA rechargeable batteries, this is not a pack, just individual batteries. It comes with 1600mah cells which last all day. I upgraded mine to 2700mah Sanyo cells ($11 at Fry's). This keeps the cost LOW, battery packs are expensive. Rechargeable AA cells are not.

It also has model Match so you won't accidentally fly a plane on the wrong settings because you forgot to change the programming. You can also label each plane, It shows up in LARGE letters what model plane you are set to. It's impossible to fly a plane on the wrong model settings.

It also has a built in timer, which is a great feature IMO.

That's why I chose the DX6i over the 6EX