I had one 2 years ago and not very good really. Packed with grease when it should be filled with oil. Have search I think people have had good results from powersteering or a company called something like that!
I know a few on EB have had steering box rebuilt by ....
http://www.power-steering.co.uk/power-steering-pumps-racks-boxes/?kw=steering%20box&fl=369445&ci=2075622517&network=s" onclick="window.open(this.href);return false;
If you PM Strongy hes been running a box reconned by power steering for atleast 2 years so should give a good indication of reliance.....
as said any Megabug boxes I've heard of seem to have been packed out with grease, great it initially removes the sloppyness but can increase the wear as the preasure from the gears blows the grease out of the seal.....I cant comment on the degree of refurbishment they undertake though.....
The megabug reconditioned steering boxes are made of cheese, I've had one which has seen very limited milage and it's already showing signs of wear.
Depending on what else you plan to do to the van and what kind of condition your front suspension is in, if you start tallying up the cost of a steering box, lowered beam with new ball joints etc then it's almost worth bridging the difference and looking at the Red9 wishbone set up.