salaam
there shouldn't be any issue in using beads, and we agree with adley when he implied, provided you don't depend on it to remember (zikr) Allah.
there would, methink, be a big problem when one uses the beads to 'calculate' the quantum of remembrance (say 33, 333, 7,000, 70,000, etc.) we are of the understanding that there shouldn't be any limit in remembering Allah, for His grace and mercy upon us has been limitless or boundless. we should perhaps learn from the malaikat, and the animals - always sing and praise His glory, and thank Him for all the grace and mercy that He has betowed upon us.
joe