Well in my opinion,
portsnap is faster, but it does keep another copy of the entire ports tree under
/var. Then again,
svn is a large port. But if you plan on tracking -STABLE, you'll need
svn anyway and then there is no need to keep two tools that essentially do the same job.
Also,
portsnap might 1) have an occasional
hiccup, and 2) is not giving the true current version of ports (usually it's a few hours behind). With
svn, you get the "freshest" of the fresh.
Back to the speed comparison:
svn is slower, especially if there are lot of updates (if you didn't update your ports tree in like 3 days), otherwise it's pretty cool. You feel the sluggishness especially on the beginning: when you do
# svn up /usr/{ports,src}
for example, on the beginning just halts for a while. I guess it's checking for changes port by port whereas
portsnap just takes the snapshot. But maybe it's just a feeling. I haven't used
portsnap for quite a while now and I don't even keep it in my world anymore, so maybe I'm not the one to talk about it
