Load compiled of some of Metallica's best work, whether they sold out. Sure its not fast but who's to say that Master of Puppets is their best album. AJFA is probably the worst production on an album IMO until St. Anger.
Musically Load has a lot of great riffs and hooks. Is it as complexed as Lightning or Puppets. No, but it was well structured and you can tell this album made the band matured sonically. Each song is played out to their length as a problem with most of their songs on every album previously.
While there are flaws in the album it self (Cure, Poor Twisted Me and Wasting My Hate) the album contains hidden gems such as The Outlaw Torn, Bleeding Me, Aint My Bitch that makes the album more enjoyable listening to it.
The only album that had this much replay value was Kill Em All basically Dave Mustaine wrote half of the shit on the album. Ride the Lightning had some decent songs on there, but half of it was filler, and Master of Puppets have some great songs as well, but it would be better if both albums were combined into one.