When i had the same situation of selecting the current day's inserted or updated record which was fetched by using Update Timestamp in table.
My DBA recommended BETWEEN is better than <,> for performance .
So as earler mentioned by Dick,your DBA can give you the 'best' solution than us.
And DBA takes the decision based on the table structure and nature of data population. For example if that date column is part of the key and or an index is defined on that or that date column is say record update date then between will work better. If that date column is something like record insert date then most likey > < is going to be more efficient.