Easy to claim. Hell of a lot harder to actually substantiate that claim.
Not hard at all, many many many different people have
independently observed it. What do you consider
substantiation? We do in fact know that there is a higher
latency from a radio communication than over wire. It is
measurable, repeatable, satisfies every criteria of
scientific proof except on Planet Rod.
Bet you couldnt pick it in a proper double blind trial or you have a faulty MX700.
Then you'd lose.
I admit I'm probably more picky about mice than the average
user, and after the recent Google checkout discounts at
buy.com and other seasonal sales I bought quite a few
cordless Logitechs dirt cheap recently in addition to those
I already had.
hmm.... LX710 Laser, G7, V200, pre-V200 (looks almost
identical but red LED type), LX5, Mediaplay, MX700,
whatever-its-called-from-EX110-set. Some of these I did
already have, the pre-V200/Mediaplay/MX700, but comparing
them I see consistent performance differences based on the
optical engine used, none are faulty though the V200, LX5
and Mediaplay are all three significantly pickier about the
mousing surface but that's a different kind of response
problem. It's not the environment either, I've taken
several along with my notebook and the slight lag is still
present.
If you don't notice it, consider yourself fortunate. I'm
not really knocking the MX700, I do like it as I'm not
"opposed" to cordless mice at all, I'm even using one at the
moment - but not for anything demanding high precision.