Looks like the 7mm XL is a great match with Newtonians
. The best references are those where the EP in question has been used in the scope design you are using, like gb wrote.
Don't dish Hyperions (Stratus - same EP) outright. Like many EPs, they are very scope specific. They are best matched with SCTs, with the only exception being the 5mm which is actually very good in Newts. I'm sure there are better performers in SCTs than these, but they are good value from the used market if the purse strings are tight.