Well, since nobody actually answered, I bought both!
The PowerPlay is only slightly larger than the PowerAccess. The Play has larger, longer tips. However, they're actually several mm thinner than the PowerAccess pliers. The Play has rounded scales that make it more comfortable to hold and bear down on, but they also add width. The handles are deeper and the tools are larger as well. The OHO tools especially are very large. The two blades are exceptional. Large, useful, and sharp.
The phillips driver in the Access is better. The one in the Play is not formed as well. It comes to too sharp a tip and the flutes are just not as well formed. It cams out of screws FAR more easily than the Access driver. The tool locks on the Play are annoying. They require both thumb and index finger pressing on both lock nubs in order to unlock the tools. It's awkward and painful, but it's also something you'll probably get used to quickly. The Access lock is super easy to press and in the right place. But sometimes if tools clump the tool can move past the lock tab and open too far. No biggie, just close the other tools and it locks back properly.The file in the Access is really good, the file in the Play is completely useless.
Large PE and SE OHO blades
Rounded handles, comfortable to hold both open and closed
Comes with two sheaths
Bigger tools all around
No pocket clip
Thinner (and thus weaker) pliers
Half are inside tools
Phillips driver could be better
Somewhat awkward to open tools, and some require opening other tools before their nail nicks are exposed
Painful, awkward tool unlock buttons
Identically sized pliers, but smaller and lighter form factor
File is well formed and works great
Excellent phillips driver
All tools open on outside
Easy to open tools, all have a nail nick. Intuitive to thumb lock while pulling on tool to make it easier to grab with a nail
Less comfortable to hold
No OHO tools
Tools are physically smaller. Blade is more like a letter opener
Slightly more flex to frame (BUT it has a notch that helps reduce flex)
The two tools are really close in versatility and use. It really comes down to what you want more. A pocket clip and a good file in a compact package, or big knives and a saw with more comfortable handles.
Personally, I think the PowerAccess is the winner because of the slimness, pocket clip, excellent file, and superior phillips. But if I had to use the tool all day, the PowerPlay is a lot easier on the hands... except the thumb. My thumb still hurts from that stupid tool lock. It might be closer if the PowerPlay had a usable file, but only slightly.