Nothing wrong with a hitch climber. I still climb on one a couple times a month just to keep it fresh in my memory. Stone ages would be tautline/Blake's but nothing wrong with that system either. I'll be starting my 8 year old daughter with that and moving her up to hitch climber and maybe eventually a mechanical if she sticks with it.
Tautline/Blake's and hitch climber vs. Mechanical is really a stationary Rope System (SRS) vs. Moving Rope System (MRS) philosophy of use debate. I prefer SRS because it's super easy to pull a rope through a branch union, anchor it to the base of the tree, and fly vs. Having to isolate a branch so both legs of the climb line can be used in a MRS. Really just a personal preference thing. Initially I didn't like mechanical anything in my system, but after running a hitch climber pulley for a while I gradually came around and started using a mechanical ascender, but there's nothing wrong with using a rope wrench/hitch/hitch climber pully.
I have an Akimbo that I use for a lanyard adjuster/work position and second short climb system on a 20 foot lanyard. I really didn't like it as an everyday ascender because I found it very picky which rope it would run well with.
I have a rope runner pro that I've climbed a few times with. Really I'm not in love with it. It's fiddly to install a climb line on, so the in tree midline attachment characteristics are kind of negated. It does run up the rope very smooth though and feels built well enough and maybe it would grow on me if I use it more. I may end up using it on my lanyard instead of the akimbo.
I mainly use a mechanical called a Bulldog Bone
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Built by a brilliant guy down in South Carolina out of aluminum and steel. It's pretty much bombproof. Just feels very solid and well built. In short I can trust it and that's what really counts for me. For reference the carabiner attaches to a rated ring on my saddle bridge.
As far as swivels go I don't have a problem using a high quality swivel from a know good manufacturer for life support. I wouldn't trust my life to a no name Chinese swivel. The swivel in the pic is a rock exotica nano. Again pretty bulletproof. I'd be surprised if it didn't meet the 23kn rating in both pull and side impact. I also run a cmi California swivel on my secondary bridge...
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Works great for switching to a MRS from a SRS. Again bombproof.
@Thumper88 do you have a tree work supply shop near by so you can try a rope runner pro out? If your coming from a Blake's you might want to consider a rope wrench hitch climber combo. You can still climb MRS and switch to SRS when your ready.