@KevlarCoated
Hi, we usually respond here frequently but I have to admit, Chris and I took an early weekend off to get in some diving.
We send all new regulator sets with service kits, so you shouldn't need kits until the 400dive/4yr mark. Access is quite easy, as worldwide shipping for a set of kits isn't all that expensive. Anyone who can service a balanced diaphragm regulator can service ours. We freely publish our service manual online and offer help to any technician that calls.
Some of the options you mention are great regulators. I feel our regulator offers advantages and improvements over many of the designs mentioned, but that is up to the diver to decide. For example we have TiCN PVD coating for durability on top of the chrome, our special HP Seat with Teflon coating and a Teflon O-ring in the balance chamber, both of which improve the breathing cycle characteristics from the first stage. We have an elongated swivel turret which helps improve hose routing in sidemount and back mount On the second stage we have the turbine piston which improves ease of service and the breathing dynamics. Other than these features we offer the free set of service kits mentioned previously, and a free first service if you decide to send it to us.
The DS4 is a good regulator choice, however the DS4 isn't really a direct comparison to the Signature as it doesn't have all of the above features mentioned (Swivel Turret, TiCN coating, Teflon HP Seat, Teflon Balance O-ring, Free Service Kits, Free First Service). It is probably more accurately compared to our Scribble series regulator in most respects, as it is a standard balanced diaphragm design.
I am sure you will be happy with whichever choice you make. Honestly, we prefer if people do not buy our products if they have doubts, as we think everyone should dive what they are comfortable with. If you have any questions I would be happy to help.
Cheers,
Landon
