Anybody can tell the similarity?

I think SL had some really good lyrics actually, face of melinda is a pretty good example especially the last lines
 
oh, while the complete concept of opeth lyrics might be a bit wierd sometimes, I do think they have great lines in many songs. For instance, the leper affinity:

"Your body is mine to avail
Such a tragic sight you are"

I think these 2 lines are very descriptive. They clearly convey the feeling of a dominant force (or something similar) and a victim, which the song is about and it strongly connects to the concept of the song and the title.
 
hardly. what has opeth's lyrics got to do with philosophy?

SL and MAYH are good concept albums with strong storylines. some small bits here and there in songs are hard to decipher and very obscure (but thats evident in MANY songs...in leonard cohen's, REM's, radiohead's etc. thats the price you pay for being literary and poetic!) but overall the concepts are very solid.

Yes, I was being sarcastic - what I'm saying is some people interpret the obscure nonsense in some of the songs as incredibly deep and intelligent just because it's way over their heads. But tbh the more nonsensical lyrics in those albums are just straight nonsense.

Personally I think Opeth writes good metal lyrics but I do feel obliged to point out to trolls like Kamel that they're not some godly work of poetry.