in the present day bitcoin transaction is slow.but if u are comparing that with credit card transaction it is too slow ..it may take some while to cope up with the same transaction speed with that of bitcoin .well i can assure that in the near future people will transact through bitcoins and it will be same as the bitcoin transaction and convinient too ..kudoos 
If we compare all online payment methods then bitcoin is not the faster nor the slowest one, so in average bitcoin is pretty good fast and not slow, but we know that there are much faster ways like credit cards, paypal etc which are instant.