Some people have referred to the recently released Casio GA2300 as the new Casioak. It does have several similarities to the GA2100, but how do they compare side by side? After reviewing GA2100HD-8A and GA2300-1A individually, I wanted to offer a review and photo comparison.
GA2100 vs GA2300 First Impressions
Both watches have a similar shape and are slimmer than your typical G-Shock. GA2300 loses the octagonal bezel, however, and doesn't have an integrated strap. I like this fact, as I can install StrapHabit 24mm FKM rubber straps on it, but it means that it doesn't have the AP Royal Oak look that earned the GA2100 Casioak its nickname.
The GA2100 looks more stylish, while the GA2300 has a more modern look. The case and strap are smoother, and I think preview the direction that the G-Shock brand is headed.
GA2100 vs GA2300 Details
Besides the case shape, the most noticeable difference between the models is the dial. GA2100 models feature flat dials with a single LCD.
GA2300 dials are divided by a large X. The LCDs are split, and the analog day display is in its own segment.
If both watches were the same color, legibility would be very similar. The GA2100 might get a slight nod because the X on the GA2300's dial is a bit distracting. The color of the hands against the dial has a lot more of an impact, however. This determines how quickly you can read the time.
At night, both watches have similar lume and LED illumination. The GA2100HD shown here has a lume dial, but nighttime legibility should be very similar between GA2300 and a standard GA2100.
Wearing GA2100 and GA2300
The GA2300 is much more comfortable. Besides being smaller and lighter, the strap makes it a better wearing experience.
It is more flexible and allows the watch to move around with your wrist more.
GA2100 vs. GA2300 Straps and Replacement Straps
Both watches feature resin straps. The integrated strap on the 2100 tends to pull my arm hair where it meets the case.
GA2300's lugs are separated, and smooth on the back side, giving it the nod for comfort.
You can also replace the GA2300 strap with any standard 24mm strap, such as our FKM rubber Smooth and Ridge straps. You can see a few photos and purchase these straps below.
GA2100 vs. GA2300 Movements
While the modules are different between these models, they have the same functions and layout. The LCDs on GA2300 are just split, rather than one single LCD on GA2100.
You can also see the width difference here. 
What is better? GA2100 vs. GA2300
I find the GA2300 to be more comfortable, and I, of course, like that you can easily swap out the strap.
The GA2100 does look a lot cooler in my eyes, though. Currently, it is also available in many more colors and materials than the still-new GA2300.
The decision will come down to which style you prefer, and how important it is to swap straps.
| Casioak | New Model | |
| Reference Numbers | GA2100HD-8A | GA2300-1A |
| Price (USD) | $110 | TBD (~$128) |
| Width (mm) | 45.4 | 42.1 |
| Height (mm) | 48.5 | 45.4 |
| Thickness (mm) | 11.8 | 11.6 |
| Module Number | 5611 | 5725 |
| Water Resistance (m) | 200 | 200 |
| Crystal | Mineral | Mineral |
| Weight (g) | 51 | 49 |
| Battery Life (years) | 3 | 3 |
Shop Casio G-Shock BGA2300 Replacement Straps:
Ridge FKM Rubber
Smooth FKM Rubber
