I have noticed that some brokers use 5 and 3 digits in the prices of currency pairs, while others use 4 and 2 digits. For example: (EURUSD @ 1.25646 and USDJPY @ 79.363 against EURUSD @ 1.2564 and USDJPY @ 79.36) Why is this so and which one to choose in this case?
It depends on the type of account they have and the Actual spreads offered.
While i would prefer 5 digit broker still i will look for the overall Spread that i am paying for each closed 1 lot on EURUSD.
5 digit and 3 digit currency prices are for those who are looking for scalping with modest gains.
This is just a matter of the broker deciding on different quotation formats. The 5 and 3 digit quotes are quoting what is known as fractional pips or pipettes. Whereas the 4 and 2 digit quotes are showing the smallest change as pips.
The difference is minimal but if you are a scalper it can be significant. I trade on the daily TF so I chose the 4 digit option as the fractional pips make no real difference to me but you should be able to ask your broker for one or the other according to your preference.