[RC-Monster Mike]

I agree that their seems to be no "standard" for providing the individual cell and/or pack ratings on Lipos - one manufacturer's "20c" pack is another's "15c" pack, and without reliable test equipment and a controlled environment, the information is somewhat useless and speculative - purchase decisions must be made largely based on whether or not the customer "believes" the ratings posted by the pack manufacturer - based on other's opinions and experience I guess.
I test my batteries in actual use with an Eagle tree data logger - before anyone asks, I don't plan to post graphs, but rather I use the information to make recommendations to customers who ask - I do take the job seriously when someone has a particular application and is seeking advice on a "safe" setup, and a 12c pack in the right capacity and application is often times a better choice for the consumer than a 25c pack with less capacity - ultimately depends on the customer's end goal.

I test everything in the same manner - starting with a fully charged pack at ambient temperature and discharging it in harsh use until it trips the LVC. I then scroll through the data to see pack voltage at given amp draw throughout the run(10 frames/second). I also test multiple cells/packs in any given session - same day, same temps, same conditions - this way I am "apples to apples" as much as possible.
In RC Cars and trucks, burst rate capacity is more important than constant discharge rate IMO - the average draw of any given run is typically below 30 amps, but I see spikes beyond 180 amps throughout the run. 100 amps continuos draw would yield a 3 minute runtime at 100% through-put with a 5000mah pack - this just ain't gonna happen, and is therefore fairly useless IMO.
I make by judgements based on whether or not the pack can maintain 3volts/cell throughout the run. Constant discharge rate isn't important(or possible to record with my method), so long as the pack can maintain 3 volts/cell throughout the run - at least this is my opinion. If it can't, then the pack isn't suggested for the application, regardless of its posted specs.
I have tested packs from every brand listed on my site(and then some), though I have not tested every individual pack. PolyQuest, Flightpower and NeuEnergy packs all have handled beyond their stated burst rates(at least up to 175 amps, which the most I can accurately measure - special praise to the PQ2500 packs, which maintain 3volts/cells up to about 70c!!). I have some other cells "in testing" that have exceeded the above packs significantly as well, but long term testing is still under way.
Anyway, these are my thoughts - until a standardized and non-biased test system comes into play, the only info I trust is what I can prove in actual use. :)