Which set is better for tournament play?

The My Fair Mahjong racks. The 20-inch length and 1.5-inch tile clearance fit larger tournament tile sets, and the magnetic pushers come apart for tight table space.

Both are acrylic and wear the same way: they scratch, crack or chip if dropped. The My Fair Mahjong racks have no reported fit problems, while some Oh My Mahjong racks do not close flush.

Is the Oh My Mahjong set worth stepping up to?

Step up if attached pushers and the included bag matter to you. If you want a longer rack and detachable pushers, the My Fair Mahjong set is the better fit.

Do the pushers come off?

On the Oh My Mahjong set, no. They are attached to the racks. On the My Fair Mahjong set, the pushers are magnetic and lift off.

Will either set hold standard American mahjong tiles?

Yes. Both are built for American mahjong. The My Fair Mahjong shelf states it holds tiles up to 1.5 inches tall; the Oh My Mahjong set does not list a tile height.

Oh My Mahjong Acrylic Rack & Pusher Set vs My Fair Mahjong Acrylic Racks

Buy the Oh My Mahjong set if you want pushers permanently attached to each rack and a storage bag in the box. Buy the My Fair Mahjong racks if you want magnetic pushers that detach, a longer 20-inch rack, and a shelf that holds tiles up to 1.5 inches tall. Both are acrylic sets of four and both scratch or chip if dropped. The Oh My Mahjong set has more owner feedback and a 4.5 rating, but some buyers report racks that do not close flush.

Choose the Oh My Mahjong set if you want attached pushers you cannot lose and a drawstring bag included.
Choose the My Fair Mahjong racks if you want detachable magnetic pushers and a longer rack for taller tiles.

Prices

Oh My Mahjong Acrylic Rack & Pusher Set: $17.79 at Amazon (checked today)
My Fair Mahjong Acrylic Racks: $17.79 at Amazon (checked today)
Difference: both cost the same today