This parity comes in 2 forms; one green square on the all blue face and one blue on the all green, assuming everything else on the puzzle is solved. If these 2 squares are directly opposite each other on the puzzle, you have 'snake eyes' ; that is head heavy, tail light. If the 2 squares are at opposite ends of the two 5x4 faces the puzzle is balanced. As far as I can tell, you can't solve this parity without switching from the balanced form to the snake eyes formation. This is easy and you should be able to switch back and fourth between these two forms if you were able to get this far. Switch to snake eye form. With everything else solved on the puzzle, apply the algorithm to the top two layers. This algorithm is the one used on your 3x3x4 and similar puzzles when none of the colors on the edges or corners match. Practice on your 3x3x4 until you're confident. Now apply it to the top two layers of your 3x4x5 remembering the outer corners and edges are 2 pieces fused together to make one piece; so don't let the shape shifting throw you; it's the exact same algorithm. Now bring the mono-colored pieces on the two 5x4 faces back to snake eyes. Now switch from snake eyes to the balanced form and apply the same algorithm to the same top 2 layers. The puzzle is now easily solved using moves and algorithms you already know. Keep in mind this parity is tough and makes this cuboid harder than the 4x4x6 cuboid even though they are much different.

I had no complaints until I started encountering certain configurations where the 2 outer extended layers of the 5 side bandage together even when in the proper shape. It sounds like this was a big problem with the mf8 2x3x4 as well several years ago, and required replacing some internal parts to fix it, though the 2x3x4 parts were eventually installed correctly from the factory and supposedly isn't an issue anymore. It appears this same factory fix has NOT yet been addressed for the 3x4x5, so it is not actually fully functional out of the box.

The bandaging is pretty infrequent and doesn't happen nearly as often as the original bad version of the 2x3x4 appeared to, but when you do encounter it it will inevitably be in the middle step of the brick parity algorithm when it hurts the most and prevents you from finishing the alg. You can try cycling through some corner cycles algs that shapeshift and resolve the corners to see if that unbandages it, but it's inconsistent and doesn't always work.

So every brick parity alg requires crossing your fingers when you get to the middle slice move and hope it isn't bandaged. Luckily it only happens once every several parity algs, but happens enough to be extremely irritating. So far I've only seen the bandaging between the outer 2 layers on the 5 side - I haven't seen it between layers on the 4 side or know if the internals would actually allow it there in certain configuration or not.

There is information online about the bandaging on the original bad release of the 2x3x4, but seems to be very little information online about the 3x4x5 bandaging or how to work around it, and as of 2020 the 3x4x5 seems to still be a very niche puzzle.

I have both the transparent and black versions of this cuboid. Both turned very well (though the transparent was a bit more crisp and a little bit faster, but these puzzles obviously aren't for speed solving so it's not a big deal) and I only experienced minor popping on a few select pieces. Tighten it up a little, and this makes a great puzzle for any cuboid fan. Would've rated higher if it didn't have the popping issue, but that's the only reason.

Broke from no effort and locked up a lot when it worked. Wouldn’t recommend unfortunately

I never owned a cuboid outside the 2x2x3 before so I thought this would be a fun challenge.After a few weeks of struggling a piece came out, no big deal right, wrong. The entire puzzles then fell apart and is currently sitting in a bag on my desk.
I think it's a great puzzle but it loses some stars for the breaking.

I love this brick. It turns great, but pieces are a bit loose. Not made for speed. A piece will fall out occasionally. Just turn calmly, not too aggressively, and it will turn very smooth and easy. Very fun to solve. Must know cuboid algorithms and brick parity algorithm. Since it is the only 3x4x5 available, I rate it 5 stars. Also buy the 2x3x4... it is very stable.

This puzzle turns very smoothly and is a great pleasure to solve. A classic cuboid even though shape shifting is not full. I have experienced a few small pops in which one or two pieces come out but a remarkably made cuboid.

poop

This cube is the most fun to solve out of all the cubes I own every solve is completely different nothing is ever the same

Best