I think the two best values in regulators on the market today are the Atomic Z2 (not Z3) and the Deep6 Gear Signature series.
The Deep6 is better suited for tech use.
But, honestly, if you're going to go tech, you're probably going to end up with a dedicated set of regs for that and a separate reg set for single tank recreational use. So, you could buy an Atomic Z2 set now and then just know that you'll buy another set of something else later, for tech. The Atomic M1 is a great reg for tech use. Or you could buy a Deep6 set now and then another 1 or 2 Deep6 sets later...
I have two sets of regs for diving doubles. A set of ScubaPro Mk 25 EVO+G260, and a set of Atomic M1. They are both fantastic for tech diving. The Atomic are arguably a little better because they are sealed. And they are, I believe, less expensive than the ScubaPro regs I mentioned. Those and the Deep6 regs all have a swivel turret and 5th (bottom) LP port. Regs with the swivel and bottom port give you the most flexibility for ideal hose routing. I considered going with regs like the ScubaPro Mk 17 when I got my first doubles regs. I didn't because the Mk 17 has neither a swivel turret nor a bottom port. The result is hose routing on a twinset (i.e. back mount doubles) that is not nearly as nice as the hose routing you get with a swivel turret and bottom port.
As for doing your own service - well... I went to ScubaPro reg tech school. I COULD service my own. But, good regs probably only need to be serviced every 2 or 3 years, at the most. When I looked at buying all the tools and instruments needed to service my own, and then considered how often I would use it all, and then thought about whether I want to dive regs that have been serviced by someone who only services 3 or 4 regs once every 2 or 3 years, I decided that I would skip all that and have my regs serviced when they need it by someone who does it every day and really knows what they are doing. Just my choice for me...