A while ago I posted a build suggestion thread and here is the follow up.
This is my first DIY project and I decided to build the Overnight Sensations because of their reputation.  I initially thought I wanted a slightly larger woofer (around 6") but I compromised a bit and I'm quite happy with the results.  I think the 4" Hivi woofers are very detailed sounding for their price, and I'm quite happy with their sound.  At first I was a bit worried about the tweeter because it sounded harsh and very sibilant with some vocals and cymbals.  After 2 or 3 weeks of listening the harshness mostly went away.
I've been listening to them for about 2 and a half months now.  I only intended them to be kind of a practice project and value benchmark for future designs, but still I'm not really eager to move onto my next build.  They're quite easy to listen to.
I plan on countersinking the drivers and painting them black eventually.  The design called for 1/2 inch MDF but I used 3/4 inch because that was all that Home Depot had in small sheets.