Can't comment on the T7 or the Forster, but I do have a Summit.
Let me qualify my comments by saying that up to this point I have loaded mainly straight wall pistol ammo. I wet tumble my brass, and deprime all my brass before I tumble. I had a Lee Challenger that I used for some time to deprime, but the spent primer handling on that press left something to be desired. The primer residue would gum up the ram, requiring cleaning/lubing every 1000 rounds or so. I bought the Summit mainly for depriming, and with the idea that I would use it for rifle loading later.
I mounted the Summit flush with the front of the bench, and had a plastic bin mounted under the bench lip to catch the spent primers. Works great. I never liked the included plastic part they included for catching primers.
The problem with depriming lots of brass (I sometimes do 1000 at a time) is that the high mounted lever is not very ergonomic for such a repetitive task, even with the optional short lever. I was having to lift the weight of the lever AND the carriage every time.
I have since sold my Challenger press and replaced it with a Lee Classic Turret. I really like that press. I have one turret that contains both the universal decapper die, and a collet bullet puller. I can decap faster than the Summit press, and don't feel like I have gone through a workout doing so. The weight of the ram balances out the weight of the lever such that I can easily move the lever by just bending my elbow. The extra turrets are only about $12.
The RCBS is threaded for 1-1/4" x 12, and comes with an adapter for standard 7/8" dies. You can use the Hornady bushing kit, which I did, which makes swapping out dies very quick and easy.
With the linkage used on the Summit, it is not possible to use something like the RCBS collet bullet puller (which is what I have) as the linkage interferes with the puller. The Hornady cam lock puller might work.
There is no provision with the Summit to prime on the press. It would be possible to buy a ram prime die (Lee sells one) but that is more of a pain than using a hand primer.
At this point I don't plan to get rid of the Summit, I still plan to use it for rifle rounds and I think it will be great for resizing. But, I will also try out the Lee Turret to see how that compares. If I feel like the Lee Turret does as good a job as the Summit, I may sell the Summit altogether.
So far I have not mentioned that I do have a Dillon 550B that I use for 90% of my pistol reloading.