I had high hopes for this tank, as I already had two Nautilus GTs and one Nautilus GT. However, after having used it for seven months I can only conclude that the GT models work better for me.
1: The slider refill construction sounds good, but in practice it is not as good as the screw-the-top-off refill solution on the GTs. Seeing the small red triangle that shows the position of the slider is difficult in poor light conditions, and the actual slider requires a lot of finger strength. I can manage pushing it, but my wife couldn't.
2: Similarly, the push-in coil construction sounds good, but is in reality quite fiddly, requiring several failed attempts each time I have to change coil. The screw-in coil construction on the GTs is much more straight forward and quicker.
3: While the air hole ring on the GTs steps from one inner hole to the next with clear click sounds, the air hole ring on the Nautilus 3 just slides over the inner holes and you must look to ensure that the two holes are aligned. If not, no air will get through.

So, for all these reasons I will stick with the GTs and have just ordered a new GT - with the 4ml acrylic extension, of course. After more than one year's heavy use, the acrylic extensions for both the regular GT and the mini looks as new. Just as good as glass, but much lighter.

This tank is next level.. Ive been using the nautilus GT and was amazed by it.. How they combined old features with new style.. And now the nautilus 3 is the next generation of tank.. Have to say it has smoother draw.. The slide top up is great and loads easier to refill.. Push in coil lot quicker and easy than having to screw it in.. Really impressed with the design.. The classic nautilus air holes are a plus.. As dont like the slit air holes never got the hang off them to find the best draw.. And was always the reason I used the nautilus.. Brought the 4ml extension glass which is a must have to the setup... Have to say I'll be purchasing another one... Thanks so much for quick delivery and excellent service.. And the toffee sweet was nice touch..