Ultimately you will have to decide!! The point of what I wrote about is that DIP packages are dead when it comes to USB microcontrollers. (One can argue that DIP packages are dead or nearly dead in most other categories as well).

I already gave you some good ideas to chew on as to approach to consider taking. I did not mean to even begin to suggest that the two links I gave were your sole choices. There are many many choices for 8051 type USB microcontrollers. A number of those are available on evaluation boards and breakout modules. As to whether you were to move away from 8051 that really is up to you. There are a plethora of MCU choices that offer USB. Many of these also have companion evaluation boards and/or breakout modules available.

As to cheaper?? If you are talking quantity one or two the cost of parts is generally small compared to the time you will invest. Use an eval board for the one-two-prototype type activity.

As to easier?? If you are making a circuit board the foot print for a modern surface mount package is just as easy to lay down as the DIP footprint. If a circuit board is in the game plan it also becomes necessary to consider a whole batch of other production concerns such as board finish, RoHS, No Pb, cleaning considerations ... etc. Taken all together these considerations will out weigh the choice of whether you as an individual can hand solder some surface mount chip versus the selection of how you go about getting your boards built.

Keep in mind that generally speaking it is a trade off: Cheaper OR Easier.

Michael Karas