Yeah, Haga must be getting nervous right about now, and Spies is making us Yanks proud. Doha was a romp!
The A123s are perfectly happy, even thrive, when run to 90% of capacity each and every flight.
The energy density after correction for the actual percentage of capacity that may be safely used (75% versus 90%) gives only a 20% disadvantage to the A123 for energy per ounce.
If you find that for the kind of flying you do, that you only use 60 or 65% of your LiPo capacity, then try the A123s, but expect to re-prop (or up the Kv) for the lower voltage, or accept less headroom for the governor to do its job.
If you build very lightly, this will be perfectly competitive. For Sport, even the enthusiastic variety, they are just dandy.
best regards,
Dean P.