The top load Hahn requires removing the bolt hold open roll pin to put it in and take it out, doesn't it? The RRA just requires loosening a hex screw, and it drops right out when you push the mag release. Plus, the RRA can be dropped down to make C Products mags run. That's what I use - exclusively use C Prod 9mm mags with zero hiccups w/RRA blocks.
I have three RRA blocks. I got all three from ADCO - backordered and waited. No one else touches the $140 price (plus only $4 S/H). Last time I checked, RainierArms had some in stock, as did Spike's, but they are both selling them for about $160-170 shipped.
ETA: Just checked, and Rainier is out of stock.