I'm sure it depends on the program and its reputation. I have a relative out on the East Coast who did the Georgetown part-time program while he worked as a paralegal or some such thing. I may not even be applying to Georgetown, but after hearing from him about it I checked it out briefly, and their part-time program was basically how their law school got its start and it appears to be very well regarded, just like the full-time program at Georgetown. My relative graduated years ago from Georgetown, not sure how long ago, but he was hired on at a large firm in Virginia, made partner, and is now head of the firm ( = $$$). So, I would not say that Georgetown's night school hampers you in any way, though you may not be able to intern/clerk as early because you will not have taken as many courses.
So if you listen to the legal professionals I talked to, get it over with. If you think you can work like a dog and rise above, go for PT if that works for you. However, it is important to remember that part time is ALMOST full time anyway. You are getting about 20 credits v. 30 and have MUCH less than 1/2 the time to work on it.