I have the 4.5-28×52 HM mounted on top of my AAA Evol Mini 22. I wanted more of a compact scope to match the gun and of course, something that will focus down to 10 yards which it does. The weight on the 4.5-28×52 is not bad at all coming in at 29.8 ounces considering it's a 34mm tube.
I'm not sure exactly how the 5-42 locking turrets work and maybe need to do some research on it. While on Snipershide, I did recall one review where they did mention that they would have like to have seen the locking turrets of the 5-42 also on the 4.5-28x52.
I honestly don't mind not having locking turrets for elevation as long as they don't get bumped out of position. For windage, a locking or capped turret is fine with me. As far as optical clarity, I haven't had enough time with it and only looked through my 4.5-28 within airgun ranges. I don't live in an area that allows me to look at ranges longer than 150 yards.
I usually have mine set anywhere between 10-20 power but mostly shoot with it set at 12x-15× and 20x for certain targets at 50 yards. I would say it's not as sharp or crisp with it set at max power (28x). 20x works for my eyes. What I really dig is the Wide Angle lens on the High Master series. When comparing to other scopes, there is such a huge difference in FOV and makes others feel like you're looking through a toilet paper tube. I also like the FML-TR1 reticle with the .075 MIL floating dot. I think it's the perfect size for my eyes especially at lower and mid power levels.
The 4.5-28x52 HM is great in low light. I compared it to my Athlon Cronus BTR G2 a few weeks ago looking through both at a shady area with some sunlight peeking through the trees during sunset and the Cronus looked washed out compared to my March at the same magnification levels. I also have a Kahles K525i that I want to compare it to when it gets back from Austria for warranty repair.
To conclude, I wish I had the time and range to sit down with all my optics to do some comparisons during bright and low light conditions to give an honest evaluation. In your situation, I think you'll have to figure out what's more important to you and your needs. Things such as what power levels would you be mostly shooting at, shooting style, hunting, target, PRS/NRL. Choosing an optic is so subjective.
Edit:
Sitting here as I type this having my morning coffee waiting for some doves to land on a tree 56 yards away. I'm also trying out the sunshade that came with it.