the SSG69 is capable of very good and very consistent accuracy. It is a rear locking action and the barrel tenon on the SSG69 is longer than the tenon on other rear locking Steyr actions of the same vintage. That is in part because the barrel tenon on the SSG69 is not threaded and it is a press fit into the action ... this method of barrel fitting apparently contributes to the accuracy of the system and as an aside it is also used on Anschutz rimfire target rifles. Naturally the SSG is designed to withstand MUCH higher pressures than an Anschutz so the actual fitting process on the Steyr relies on the longer tenon, great pressure and a heat/shrink bond. Contrary to what you may read online the
other (non-SSG) Steyr rifles of the same action type (ie rear locking Model L, M, S) all have threaded barrel tenons and thread onto the action in the more traditional fashion. You will see if you compare an SSG action to a Model L action that the tenon on the Model L is much shorter.
Most of the weight of the SSG 69 (Particularly the PII versions with the heavier barrel) is in the action and barrel .. the stock is quite light. This makes for a rifle with excellent repeatable accuracy while remaining relatively light for field use. Compared to an AI-AX rifle -- they both shoot extremely well but one is a lot more robust while the other is a lot easier to pack over the hills.
However the trade-off is that the lighter stock on the SSG has a few known weaknesses that you should be aware of. One is that the trigger guard/bottom action (which is synthetic) can be cracked by tightening the action screws too tight and there are small synthetic tabs on this assembly to retain the magazine that can break. This is exacerbated by the use of some solvents and bug repellent which can hasten the deterioration of the stock material if you are clumsy. If you are aware of these factors and take a minimum of care while torquing the action screws and removing/replacing the magazine properly ... you will have years of trouble free shooting and will be blissfully unaware of these issues. If you are a ham handed idiot or are in the habit of throwing your firearm over cliffs or backing over it with your F350 ... then buy a Remington which is cheaper to replace.
As for the Pro Hunter ... There is a lot I dont know about that rifle ... However I do know it uses Steyr's 'SBS' action (Safe Bolt System) and this is the action that is used on most of the Steyr line now ... including the SSG04 and SSG08. It is also used on the Steyr M300 Match. All of these rifles -- and particularly the M300 Match -- are known to be extremely accurate. The M300 Match (no longer made) is of course of very special design - particularly how the barrel is fitted to the action -- but that is another story. So I would expect that the Pro Hunter will perform very well and I have never read of any complaints about accuracy with them. As far as I know all the SBS actions are designed for traditional barrel mounting - that is they are threaded, although the 'Scout' rifles have an interesting and unique method of assembly and the M300 - well is 'different' again.
I can offer that I like the SBS action magazines and that 10rd magazines are generally far less expensive and more readily available than those for the SSG69.
Cost ... while the SSG is not inexpensive it is interesting that when the rear locking action style of Steyr rifles were first designed and introduced -- it was because the previous front locking rifles produced (the Mannlicher Schoenauer 1961 and Model 72) had become very expensive to produce and the new 'rear locking' actions were significantly cheaper to build .... you will be surprised how inexpensive the early model M's were compared to more recent prices. It looks like the SBS rifles were also introduced because they provided some economies/efficiencies ... but certainly not lesser capabilities.
I have an SSG69 PII and a M300 Match. I dont see any reason to sell them and I know if I dont shoot well its not the equipment. But the reality is I would shoot a lot better with a 'lesser' rifle and more practice time. I have a friend who can pick up any rifle I own - including hunting rifles - and shoot it significantly better than I can.
In the final analysis -- your choice should be based on an emotional decision. Pick the one you really want ... then buy the other one later