I've owned a MSAR since they first came to market: 20" barrel , optic, OD stock - standard classic look. I had Ratworx upgrade it to an E4 with the metal mag release. I've added a Manticore charging handle and a 20/20 sear. The rifle functions great and no problems with the optic holding zero. I've run across a few batches of spares parts, so I'm more than set for any repairs.

I recently got a bonus and thought I would "upgrade" to a Steyr StG77. To be honest, I'm not that impressed. The fit and finish does not come close to the MSAR. rough edges, the safety digs into my hand and the ejection port cover does not want to seat properly.  I won't compare triggers because of the 20/20 sear on the MSAR. I haven't shot it yet so no report as to accuracy. The optic seems nice.

Are other Steyr AUG models similar in fit and finish or was the company trying to be historically accurate?

It may sound harsh, but the StG77 almost seems like a cheap clone of the MSAR.

As far as I understand, one of the purposes behind MSAR was to refine and upgrade the AUG. Ergonomically and esthetically the MSAR is probably nicer than a typical Steyr AUG. The parts on your stg77 are coming off the same machines and parts bins as all other guns Steyr ships across the world, which is to say that you get a functional, reliable, and durable gun. Could flashing be better taken care of, could the sharp edged safety be broken smooth, could Steyr put more attention to detail or at least do some basic upgrades? Definitely.

You have a rock solid product backed up by a solid company and an outstanding warranty.

Of the things you listed only the ejection port cover sounds off  I'm not sure what's going on with your port cover, call Steyr and they'll take care of it.

I am in the same boat as you.

MSAR fills my AUG want 100%...and once you have spare parts for the MSAR...really there is no need to replace it with a Steyr, unless you want the Steyr name and heritage...which there is nothing wrong with that one bit.

Me, personally, would never use an AUG for serious use...it has its limitations...especially weak hand side shooting...prefer my Tavor for that.

I lightly filed down the corners on the safety on mine.

Would be great if they came with upgraded sears from the factory.