TM-7s are cool, i've never used one.
i've found my A5 to be reliable, performs well enough for me, and does a great job all around.
since it hasn't been said, "Washer first, then o-ring, tombstone holds it in place." if you don't know what i mean, you will if you get an A5.
i've never used an X7 but they're just as good.
i don't know how you play speedball, but i find bushball/milsim/scenario puts more emphasis on accuracy and less on laying paint, unless you happen to play the role of heavy rifleman or fire support

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Proud Canadian Baller
Kit: A5, camo job, polished internals, 14" Smart Parts Progressive barrel. Borrowed Opsgear G36 stock. 24oz CO2 w/ remote and slide check. Neat homemade sling. MORE TO COME
Vents Goggles and Multicam