Two people making negative comments isn't that bad.
Their music IS crap. Unless if you like extremely long, meaningless songs with various clean parts and heavy parts sandwiched together and repeated over and over in an attempt to sound 'artistic'.
"repeated over and over"? Did you ever listen to BWP in one take? They progress all the time, you'll hardly notice any parts being repeated. "extremely long"? I'd hardly say 10 minutes is extremely long, unless you have some problem with listening to some lengthy songs because you can't stay focussed. Lengthy songs often give the band the time to make the songs progress, just like with classical or jazz music. Yes they have heavy parts and softer parts, that makes the music so more beautiful. I don't like music that constantly hammers into you with grunts where everyone plays as hard as they can. At least Opeth takes the time to sound heavy, but beautiful at the same time. For me, this works really well.
Sorry for going slightly off-topic here.
The only Opeth I've heard is Morningrise, and that was more then enough. For bands that are 'heavy but beautiful' there's far better, Nadja being the obvious one, The Angelic Process, Ulver, Drudkh's Autumn Aurora, hell, Mogwai, and so on and so forth. Opeth's parts are jumbled together almost completely randomly. Also: you're right, 10 minutes isn't that long in general. I have no problem with 20, 30, 60 minute long drone tracks. However, listening to random clean and heavy parts forced together with no real attempt at worthwhile progression (short of "To Bid You Farewell", which is a pretty cool song) for ten minutes is a tiring experience.
New Bongripper is good times, too.