RE: 4x scopes
Nothing wrong with a fixed 4 power scope for most deer hunting applications. I think it is funny when people balk at a fixed scope, but yet never turn up the variables past 3 or 4. I have many buddies who only use their variable higher power settings when on the range, which I might add make sighting in a lot nicer but not required. I on the other like and do increase the power when warranted, for the most part I am in the 6 power range when hunting on my 3 x 10' s, but I have taken shots at antelope and deer when on 10. The key to variables and high power is a solid rest, I do think for long range shots it does make it easier to determine crosshair placement on the vitals.
Effective range, is really determined by the hunter of any scope or gun. I would say now I would feel only effective to 150, but again I am used to higher power now. But I do know many guys who have taken game at 200 plus in the 4 power range, which would easily fit in to most deer hunting situations.
The bonus is less moving parts equals less chance for field troubles. I would also say a good fixed would be better choice than a poor variable. Another reason I use variables other than I like the increased power availablity, is the size of objective and limited light gathering capabilities due to the size of objective available. In hunting, those last few minutes of precious light need to be harnessed ( I feel), if you have a scope that dims quickly as light fades, your distance and accuracy of crosshair placement goes with it. As such I prefer those of higher than 40mms, but it is just what I am use to. If only given the choice between a poor 40 mm variable and good quality 33 mm fixed, I would opt for a fixed.