For the amount of flying necessary to get 1K benefits, it's not worth it. Certainly not worth it IMO if paying out of pocket versus steering company paid travel that direction. If you already get business class travel paid than 1K is definitely not going to give you anything worth pursuing.
You get SWUs but they are spotty to clear depending on your flight route and day of the week. International I have had bad luck as I fly on Mon and Friday. UDU again totally dependant on the airports you fly into and out-of.
As a 1P you get 100% mileage bonus and baggage allowance (as I think is appropriate) and obvioulsy E+. Additional 1K perks are minimal at best. If you go on vacation and have large family you can have everyone go in E+. Big deal.
Other then SWUs (when they clear), there just is not much there IMO. People rave about the 1K line. How do you think everybody who is not a 1K manages to get anywhere? Reservations. 1K is just not that big a deal, sorry.