Not to sound like a jerk

, but there is no challenge for high reps v. low reps.
If you have been doing low reps for a long time and you start doing higher reps, you will get stronger. It works the other way around as well.
Higher reps are always a good idea because it increases the work capacity of the muscles you are training so that your recovery time is faster when you do heavier weight.
Lower reps are always a good idea because it allows your body to adapt to heavier weight and recruit more muscle fiber.
A push press (or other explosive pressing exercise) is great as well, not just a shoulder exercise, but it will aid in the explosive power in the pressing muscles, helping your body recruit more muscle fiber in a shorter amount of time, as well as getting you used to hoisting up heavier weight that your traditional shoulder press.
Getting your body to adapt to different types of stimulus in the same training period will always produce results.
So in a 2 week period you could do low reps 2X, high reps 1X, and explosive reps 1X (providing you are training shoulders 2 days per week).
Then rotate for the next 2 weeks HR 2X, LR 1X, EX. 1X.
And again the third 2 week period EX. 2X, LR 1X, HR 1X.
Now you have 6 weeks of pressing exercises planned and all you have to do is add in the assistance exercises that are best for you.