The difference being is that every other weekend or so they have a 99p postage for club members (baisically signing up to a mailing list that gets 1 email a week). It's courier delivery in 2-5 days (think UK only?).
You should know that most cheap pioneer 106 (I got mine from ebuyer!) around are actually not true pioneers! (They are usually 106RD which are manufactured by Pioneer but have another manufacturers firmware (often ACER in UK))
Only a prob if you want to upgrade the flash (say, to making it region-free), but this can now be bypassed