Can anyone clarify the mag release on these two adapter blocks for me...my understanding is that the standard AR-15 mag button ejects the magazine?  I am debating between these two and the VM Hytech mag block fo rthe new lower I bought last night (I coulnd't help it, it was calling my name...I must have EBR disease! )

Colt pattern blocks use the AR mag release to drop the mag....

The VM Hy-Tech block is held in by the AR mag catch, and the plain Uzi mags are retained via the std Uzi mag catch.

OK, the real question is which is preferable?  Using the standard mag catch button but having to nothc $20 mags, or having to learn a different mag release button but not risking damage to the mags?

I have had both the Olympic and Colt/RRA style set ups.  I prefer the Colt/RRA style, in particular because of the mag change.  I have been using 223/5.56 ARs for a couple decades now, and when the mag runs dry, my finger immediately goes after the mag button.  On my pre-ban Oly, that had me constantly dropping my mag block.  With the Colt/RRA system, changing mags is the exact same action I use in any standard AR.
Sluggo