I will out myself and say I think almost all Symphony X before Paradise Lost is unbearable, whereas their last 3 albums are totally awesome, so they'd be my #2 here
While I'm by no means a fan, I think Symphony X up until (and including) Paradise Lost, while cheesy still did their thing pretty good. But i remember thinking the one after Paradise Lost was really painful to get through because the guitars were tuned to sound like a machine or something and the 'heavier' tuning just had a negative impact on their sound IMO. The earlier stuff is most definitely cheese but I can see why people would get something out of it more - even if me myself is fairly neutral.
Responding to both; Paradise Lost was the album that got me 'into' Symphony X when it was released in 2007. I was in high school and thought what they did was awesome. I have fond memories of this album in particular. Checking out their previous work, I dug The Odyssey and Divine Wings of Tragedy the most. I could never get my hands on 'V: The New Mythology Suite'. A shame, because years later when I finally decided to get that one after Iconoclast was such a
huge let-down I think V became my favourite SX album. I haven't listened to Iconoclast since it was released basically and kind-of lost interest in the band (I only listened to their latest one like once), but Paradise Lost is one I occasionally enjoy for nostalgic reasons and and V contains some of their best work as far as I'm concerned.
Definitely an inconsistent band as far as their studio output is concerned (I think), but some of the things they do, they do really well.