If you are looking at a straight yes/no answer - the answer is yes. Attack and defense points give 3.33% bonus instead of 5%.

Does the game takes longer? Depends on how difficulty is configured (and map size).
When generating a map there is a monster difficulty setting. If you like fast maps I suggest it is set to "Normal" or "Strong". Anything beyond that significantly increases difficulty, which increases preparation time, which increases overall game time.
Here is a quick guide on monster strength levels:

"normal" - This is for casual gaming. You can start cleaning the map since day 1 without much hesitation.
"Strong" - normal guards are nearly the same difficulty as "normal", border guards become a little tougher but the game pace is still very fast.
"Very strong" - this is for competitive play. Requires a lot of planning and strategic thought.
"Impossible" - Monsters are what it says - impossible to beat.