Just returned from a road trip to Lesotho, so here are my thoughts for anyone else planning such a trip.
Having never driven 'off - road' before, nor mounted anything more challenging than the roadside curb, I was a little daunted by the prospects of the Sani Pass and beyond, but relying (perhaps foolishly) on the innate bravado that comes with a Y chromosome, all went well.
Set off from PMB at 6.30am in a borrowed Toyota Prado, arrived at the SA border by 8.30. That part of the route had been clearly worked on compared with an aborted trip I tried to make in an unsuitable vehicle in January. From the border to the top was straightforward - never felt dangerous. The road is very passable at the moment; even saw a couple of minivan/taxis ascending without trouble. The views are, needless to say, stunning (http://youtu.be/_CMeO6u8GqU).
The road conditions thereafter where considerably worse. We drove via Mokhotlong & Butha-Buthe, arriving at Maseru at 7pm the same evening. A long day, but thoroughly enjoyable with enough stops on the way for food, photos etc. The track between Sani Pass and Mokhotlong was untarred with no obvious drainage - average speed 20kph - descent through the valley to Mokhotlong is very dramatic. From there onto Butha-Buthe the route was tarred but for most of it you really wondered why they'd bothered: More pot holes than tar - definitely the most uncomfortable part of the journey. The last 2 hours approaching Maseru, the road was in good condition.
Managed to get a day trip to Semonkong in as well - 3 hours straight from Maseru - 4x4 not essential, but very much recommended particularly if it's raining as a lot of the road is just dirt hills. The falls nearby are worth taking in.
My only advise is drive slowly.