The $99 Bosch at Lowes is a 1/2" drill - the DDB, not the DDS. It is 400 in-lb vs the 181's 600 in-lb. I have both, unless you are expecting to be doing ******** work with a 18v drill I think he'd be happy with either. Especially since he already has the impact driver.
Personally, the two extra batteries are more valuable to me than the 200 in-lbs, simply because both are great 18v tools that will **** the batteries.
I may be spoiled as I never ask too much from my 18v tools, they are great drivers and small drills, but when I have real work to do I reach for my Bosch 36v. It is several years old and was my first Lithium product to replace my Bosch 24v Nicad set, and it has been absolutely fantastic and has an insane amount of power. I will always reach for the 36v instead of an impact tool, much easier on the ears and it drives much faster anyway.