Oh, it definitely makes a difference... for roaming if you are on Sprint. We are stuck on Sprint's left-hind, VM.
Just for info, the following is by
digiblur , who runs the Every Sprint PRL thread over at xda:
Common PRL Myths
1. A PRL is not a list of towers. It's a list of
cell phone systems that your phone searches
for.
2. It will not make your phone connect to
different Sprint 3G towers.
3. It will not give you better Sprint PCS band
3G or 1X coverage.
4. It will not give you better LTE coverage.
5. An update is not required for new cellular
sites.
6. The only time a PRL update will give you
better native Sprint coverage is when
800mhz SMR (BC10) support is added and
enabled in your area.
7. You can not use AT&T or VZW LTE with a
use of a different PRL
I will quote an edited-for-length version in my sig for awhile, with a link to that thread, which contains many useful links explaining PRL in detail, in case anyone is curious.