@stanley_white Thanks highlighting this thread for me. The reason I have not posted here is that, while I have looked through several March 3-24X42 and 52, I have never used one. On the other hand, there is a March-FX 4.5-28X52 with the PDK reticle on my AR-10.
However, now that I'm here, I'll post a few thoughts.
The 3-24X42 has been around for several years and is a proven design. It weighs in around 21 ounces, where the 52mm objective will bring it up to 24 ounces. At all the SHOT shows I've attended, hunters always wanted to see the 3-24X42 and X52. They are a great solid design with lots of magnification, when that counts. They have ED lenses and have always had ED lenses. They provide for a good DOF, especially the 42mm objective. It's a great lightweight, all-around FFP riflescope.
The March-FX 4.5-28X52 HM is a different animal. It's a short design with a wide-angle eyepiece. It was intended for the PRS shooters who wanted a light short riflescope. The wide-angle eyepiece provide for an AAOV of 24° (if memory serves), which is a wider FOV than most other riflescopes on the planet. Only the March Majesta 8-80XX56 with its 25° eyepiece and the March-FX 5-42X56 HM with its 26° eyepiece have wider FOV, as far as I know. The main tube of the 4.5-28X52 is 34mm with the wall thickness at 4mm. The 3-24X42/52 is a 30mm tube with a wall thickess of 2mm. This makes the 4.5-28X52 immensely strong.
I have used my 4.5-28X52 first on an AR-15 then moved it to my AR-10 when I tried a few PRS-competitions. I discovered I was too old and arthritic to play that game. Sigh. The 4.5-28X52 does come with a large elevation turret with big numbers (great for old people), and an inner wheel for the side focus, which provides increased granularity and ease of use. The wide FOV allows you to get behind the scope quicker than usual and I spotted a lot of my many misses in the uncluttered view through the riflescope.
The large objective and short design do affect the depth of field on the 4.5-28X52 but judicious use of the side focus will mitigate that.
I now just shoot my AR-10 in target practice. If I were to go hunting deer or pig, I would use that combo; the wide FOV is great for that and I have on tap, all the magnification I would ever need.
The OP did not state a purpose for the optics.