Is Object Services good to handle big amount of data?

Hi OS Gurus,

I need to develop a program which selects data from a lot of tables and handle this data to populate some BAPIs.

I'm wondering if object services (specifically query service) would be good to fill this requirement. I don't need to use transaction service.

Will it decrease program performance? Do you think that's better to write selects statements in the report which just select data that will be used?

Thanks!