Understanding automatically tuned multi-block reads

Question: I did play around with different settings of db_file_multiblock_read_count within 10g with no appreciable results. My setting of the db_file_multiblock_read_count parameter had almost no effect on query performance, I guess this is related to a read ahead cache on os/filesystem/disk device level with at least 128 blocks.
I am concerned about switching to sequential reads with setting db_file_multiblock_read_count=0, using the new 10g feature "Automatically Tuned Multiblock Reads".
Is it already reliable to use "Automatically Tuned Multiblock Reads" with 10g or should one still run with an as high as possible setting for db_file_multiblock_read_count? Are there any drawbacks having db_file_multiblock_read_count on a high value ?
Find the answer to this question and more information on automatically tuned multi-block reads here:http://oracle-tips.c.topica.com/maakPNjabGerxbLGJrib/