The RAM mount adapter works as a secure way to mount the Nexus 7 tablet, but by the time you add all of the additional parts the price ends up being around $40. If you don’t need a mounting option that’s as rugged and want to save some money this tablet grip on ebay is only about $11.
The get a grip tablet holder isn’t anything fancy, just a mouse trap style spring and 3 rubber feet to hold your tablet in place. The grip feels secure enough to keep the tablet in place, but I’m not sure I would trust it to hold your tablet in place at speeds faster then a walk.
The 1/4 20 mount on the get a grip tablet holder is just a captive nut held in place by plastic so it probably wont handle a whole lot of stress. The 1/8 inch of plastic under the nut also requires a slightly longer stud then average, so you might have a tough time connecting this to a quick release plate with a lot of padding.
Build quality on the get a grip tablet holder is mostly thin plastic. The spring is actually strong enough to flex the plastic just a little bit when you open the clam shell up. I’ll probably end up using this mount for studio work, but you could probably get away with using it on a rig if you’re brave (or add ducktape) and don’t mind risking a $200 tablet for a $30 savings on the RAM mount adapter. I think the trade off is price v.s. build quality.