A quick reply,

I dive a YBOD, I love it, but; it has all the streamlining properties of a Tank, if you want to add additional tins for bailout, or to gas switch on return from a deep dive you have to carry them all as side slings, the exception to this is you can mount a three each side of the box.
The harness is CRAP, the placement of D rings is very poor. Aside from this it is a tried and tested unit (well the Classic is, as far as I am concerned the Evolution / Vision is too new to judge yet). A lot of people dive them, there is a reasonable aftermarket for bits and pieces and the company are, in gerneral, a dream to deal with.

The Meg on the other hand, is well strreamlined, offers a lot of options to customise it for travel / different dives and is fantastically made. The harness can be configred to suit and it is just fab.

The downside, and this is a very big one for me, is it is made in the states, spares have to come from there, you have to go there to be trained which means a solid week off work, and there is a 5 hour time difference if you have an insoluable problem.

Price wise, with the dollar as weak as it is, the Meg is a very attractive option at the moment.

To be honest, if it was me, I would be leaning towards the meg. even with the USA issue.

Andrew