We visited Butrint in mid August 2005 on a day trip from Parga in Greece. Our gude was extremely knowledgeable and genuinely helped us understand the site. This was important because the "guidebook" (effectively an expensive pamphlet at 6E) was probaly the most useless of it's type I have encountered!
The main dissapointment was that we were not able to explore, and followed a set route, which although benefiting from the guide, meant we did not see all that we would have liked. Also dissapointing was that the mosaics were all (rightly) covered with sand for protection, but there was only a very poor diagram - a photo display would have been so much better.
The other point to note is that Butrint is in a marsh, and the attendent mosquitoes are very active. We all got severely bitten, despite pleanty (we thought) insect repellent.