The Windows version of Premiere Elements 13 includes a number effects and transitions that are not available on the Mac version.

The Windows version includes 86 video effects and 23 audio effects.
The Mac version includes 71 video effects and 19 audio effects.

The following Video Effects are not included in the Mac version:
Blur: Anti-Alias, Ghosting
Distort: Bend, Lens Distortion, Ripple
Image Control: Color Pass, Color Replace
Keying: Blue Screen Key, Green Screen Key, Chroma Key, RGB Difference Key
Transform: Camera View, Clip, Horizontal Hold, Vertical Hold

The following Audio Effects are not included in the Mac version:
Denoiser, Dynamics, Pitch Shifter, Reverb

The Windows version includes 111 video transitions.
The Mac version includes 50 video transitions.

The following Video Transitions are not included in the Mac version:
3D Motion: Curtain, Doors, Fold-Up, Spin, Spin Away, Swing In, Swing Out, Tumble Away
Dissolve: Dither Dissolve, Non-Additive Dissolve, Random Invert
Iris: Iris Points, Iris Shapes, Iris Star
Map: Channel Map, Luminance Map
Page Peel: Center Peel, Peel Back, Roll Away
Slide: Band Slide, Center Merge, MultiSpin, Slash Slide, Sliding Bands, Sliding Boxes, Swap, Swirl
Special Effect: Direct, Displace, Image Mask, Take, Texturize, Three-D
Stretch: Cross Stretch, Funnel Stretch, Stretch In, Stretch Over
Wipe: Band Wipe, Checker Wip, CheckerBoard, Clock Wipe, Paint Splatter, Pinwheel, Radial Wipe, Random Blocks, Random Wipe, Spiral Boxes, Venetian Blinds, Wedge Wipe, Zig Zag Blocks
Zoom: Cross Zoom, Zoom, Zoom Boxes, Zoom Trails

Steve,
I always wanted to ask, since Apple made its name by being the "creative" person's toolset, why does it seem that the Apple offerings seem to lag relative to the PC offering? I see the same thing with the Microsoft Office Suite and others.

-Vernon

Apparently, these programs are developed for Windows first and then adapted to Macs, Vernon. Some features are apparently not possible to transition to the OSX platform.

That's as I understand it anyway.