>If the Performance in practice is not different I would prefer IN(1,2) for two reasons:
>- It is more readable (WHERE MyField IN (1,3,5,7,9,11,13,15)
>- It does not need additional parentheses if there are other expressions in the where clause

Yes, it is certainly more readable and shorter. I just do not like this additional hop in the execution plan which removes some performance percentage from the main index key.