The main differences between Maxima (Weaver style) bases and a picatinny rails are the slot depth and width dimensions (fore to aft).
Maxima (Weaver style) bases typically have 1 or 2 slots on the front base and 1 slot on the rear allowing for most scope mounting solutions.
Picatinny Rails (Mil-Spec 1913) have equally spaced slots the entire length of the base, and allow more adjustment for your rings. Picatinny rails also allow use of certain 1 piece mounts and other aiming solutions that require a picatinny interface and typically come in zero or 20MOA.
STANAG 4694 rails utilize the latest NATO standards for scope mounting interfaces. This is essentially the same design as 1913 picatinny rails, but held to tighter tolerances. paired with STANAG compliant rings creates the highest degree of rail clamping surface, and may result in better return to zero.
All Mountain Tech, Maxima Horizontal and Skyline mounts are manufactured to STANAG 4694 specifications, and are compatible with 1913 picatinny. All Mountain Tech, Maxima, Maxima Horizontal rings will fit any weaver style base as well.

(Left image) A typical weaver or picatinny style mount would attach, and make its main contact with the base on the angled sides of the base, both top and bottom, leaving a small gap between the bottom surface of the mount and the top of the base.
(Right image) STANAG 4694 mounts attach by placing pressure to the underside and flat top of the base only. NATO tests have shown that this attachment method can increase repeatable alignment. All 1913 picatinny and STANAG 4694 mounts are interchangeable and will work on either platform.
*except for CZ, Ruger, Tikka and rimfire specific rings that fit their own dovetail actions