That's a good thing, because I haven't seen this particular series before.
Megumi Hayashibara's name is quite familiar to nearly all anime fans, having voiced roles for everyone from Pikachu to Rei Ayanami, and most of the character types in between. She also has a fairly impressive discography, perhaps most notably for Slayers, and the series which is arguably a remake of it, Lost Universe.
Still, the knock I mostly have against Megumi is that a lot of her songs end up sounding the same. And while that's great, from the standpoint of those who like her songs and want more of them--stick with what works, after all--it does wear a bit sometimes.
infinity is a good example of this. It's not a song I tend to listen to a lot, not because it's bad so much as it's just... unremarkable. I'm at pains to describe it, simply because I could simply say "Listen to any Slayers song and you'll know just what it sounds like." But that's obviously not my job.
A quick intro and then the first verse, which starts out very light on instrumentals, then slowly begins to build up. It's the sort of development I rather like, and once you're into the second half, things are in full swing. In fact, it's rather cleverly done, and keeps things from getting too stale.
The chorus is the strongest part of the song, with a good bass riff, some nice backing vocals, and the string portmanteau.
I do like the bridge, but it sounds very much like the bridge from another Hayashibara song, Breeze, which I actually like more than this one (and is from the Slayers series I saw first). It doesn't really last too long, though, which is unfortunate. Instead, we go into the conclusion of the song, which is rather weak, in comparison.
Three of five stars. If this was the only song Megumi did, it would be great, but that there are so many others makes it a bit dull.