If you're just plinking, fun comp, and messing around the PIG is fine (never used the HOG).
But when you are wanting a serious shot (hunting, tactical, etc) I've found the PIG saddle (real one, not knock off) wiggles a bit too much for me. the pads make for kind of awkward movement
ARCA rail is a solid attachment and the way I would go for a "primary" rifle used for serious/expensive purposes.
The PIG type saddle allows for pretty much any rifle, but it's limitations pop up pretty quick in usage.
My top recommendation is an RSS anvil. even with cheapie tripod legs and a saddle type attachment.
the speed and fine tuning of the Anvil is awesome.
I'd prioritize getting the Anvil head over anything else. the attachment is secondary for me, and the legs provided thick enough are the last part of the equation
though others will have differing opinions and are probably more correct
for ease of use, I love the Anvil head + whatever else
I run an ARCA rail + Anvil + 34L at this time- which works great to hold my rifle like an art piece. It works fine for shooting.
Gotta have priorities straight.