In the myrad of cb750s I have owned I have run Ohlins, Marzocchi, Hagons, Progressives (412s and magnums), Mullhollands, vipex, Works, Koni (alloy bodies and shields), and redwings.
Of those shocks, the only ones still available new are Ohlins, Progressives, Works, and Hagons. When you see the price of ohlins or works ($600+ starting) you will quickly realize they are an overkill option and best suited for a track racer who isn't on a budget. The 412's are only slightly nicer than the stock shocks and I attribute this to better fork oil. Plus propert weight springs were extra. The Hagons I have were far and away the best deal - valved for weight at no extra cost (a Dave Quinn feature, not every hagon dealer does this). They are an excellent shock and honestly add a lot of curb appeal to the bike as well as great riding experience. You should pair them with a set of cartridge emulators for the forks.
Shocks are a funny thing, I have never seen a good pair of shocks looked upon as a negative but I have seen people "impressed" with ohlins, marzocchi stradas, and even my hagons. My mullhollands have been one of the best riding/wearing shocks but everyone mistakes them for stock (not a bad thing) because most people don't know what a stock shock should look like anyway.