Bits with a 1/2" shank are stronger & provide less vibration. Larger profiles are also found with the 1/2" shank. You will find smaller profiles have a 1/4" shank. If I have the same profile available in both sizes I will get the 1/2". After awhile you will have bits with both sizes in your collection & each being the perfect size for the job.
If you were to want to make miniature dove tails with a jig, you will need a bit with a 1/4" shank as the 1/2" shank would be to large the fit thru the tails of the joint. The router you are getting will be able to handle any bit you need to use at the time.
I use an 1/8" roundover frequently & have one set up in a trim router with a 1/4" collet at all times. It's light & easy to handle.
Have a nice & safe day!
Last edited by jlord; 01-21-2012 at 02:06 PM.