My understanding is the EP5 uses Japanese-made lenses, while the others use Chinese lenses (nominally lower quality). The EP5 has a 56 mm objective while the SH4 is 50 mm. Unless shooting in lower light conditions, that will not provide a significant benefit. Obviously a significant price difference. I have an EP5, and am considering a SH4 to put on a precision rimfire.
Follow up: I bought the SH-4J 6-24x50 (Japanese lenses) and use it on my primary precision rimfire rifle. I've been using it for 4 months every week and have had no issues at all. The only little thing is the parallax adjust gets very stiff when the temperature drops into the below 30°F range. I haven't tried the "heat with hair dryer and work it back and forth" process that is supposed to help yet.
The easiest way is to compare the specs for both scopes.
My understanding is the EP5 uses Japanese-made lenses, while the others use Chinese lenses (nominally lower quality). The EP5 has a 56 mm objective while the SH4 is 50 mm. Unless shooting in lower light conditions, that will not provide a significant benefit. Obviously a significant price difference. I have an EP5, and am considering a SH4 to put on a precision rimfire.
The EP5 has a 56mm objective, Japanese ED glass, and a full 10 MIL per revolution on the elevation turret.
The SH4 has a 50mm objective, Chinese HD glass, and 8 MIL per revolution,
Both are great scopes, but the EP5 is the dominate one of the bunch.