Egos actually put out 3.2v... if you want a TRUE 3.7v device, you'll need a mod or passthrough. I have the Icon's big brother, the Prodigy v3.1 and I love it. The Icon and Prodigy are built similarly, so I know you wont be disappointed.
Also, some folks have experienced battery failure when using "fat battery" mods like the Ego/Riva paired with LR attys. This wont be an issue with a true 3.7v device.
Have you tried 6v? I bought the prodigy because it was capable of 3.7v and 6v vaping with the same device. I wanted to try both. Honestly, I love them both...
Proidgy w/ a 3.7v AW 17670 battery (1600 mah) paired with a Cisco LR 306 (fits 510 threads) @ 1.5 ohms = ~9 watts
Prodigy w/ 2x AW LiFePO4 3v batteries (500 mah) for 6v vaping with Ikenvape 306 @ 3.5 ohms = ~10watts
@ 3.7v with the 17670 battery setup, I can vape for 2-3 days without charging... and the Cisco 1.5ohm 306s (Avidvaper.com) truly are amazing... but it's a drip setup which is sort of high-maintenance
@6v, the pair of 500mah batteries lasts me a day and I'm a pretty heavy vaper. The hits are extremely satisfying, so I vape a bit less @6v.
Your Ego @ 3.2v with a standard atty (lets say 2.8 ohms) = ~4 watts
Your Ego @ 3.2v with a low-res atty (lets say 2 ohms) = ~5 watts
Most people find their "sweet spot" (which is the most satisfying flavor, vapor, vapor temperature, and throat hit) between 7-10 watts.
I used a regular Joye 510 and an Ego... and I never knew what I was missing. Getting a mod with the proper atty resistance was a whole new world of vaping... I hope you try it!
Also, the 3.7v device with a nice battery is great for cartos at standard or low resistance... very satisfying.
EDIT: The short answer is that this will NOT be the same vape in a shiny package... The Icon is purely mechanical device... the Ego has wires and circuitry inside that can go bad. The basic components of the Icon are much more durable. The only thing that will eventually wear out is your battery and, of course, atomizer.
Also, you will notice a big difference... as you're bumping up your vaping wattage significantly... especially if you use their high-drawin AW IMR batteries!