If you've got Bite, it'll work with ISX. You can set it as your quick reply option in the ISX settings app.
Personally I keep switching between the two. I just can't decide. I LOVE the look of ISX and Messages+. Looks very iOS like and integrates well. I also really like the top shelf feature with the quick settings toggles. They look really nice and blend well with iOS and the ISX app. The twitter/mail/RSS plugins are pretty cool, but the reader doesn't sync with google reader which make it useless for me, the mail plugin doesn't handle HTML at all so it sucks too. I've used the twitter plugin but I'm not sold on it, yet.
I don't like that the quick reply for Messages+ automatically marks the message as read when you open it. Sometimes I start typing and have to stop without sending the message and I'd rather not lose what I've typed/have to open the quick compose, type in the name, see the conversation and THEN reply. Kind of annoying. Also not a fan of how hidden album art is when it's behind ISX on the lock screen, but thats not really a HUGE issue.
Lockinfo just has that familiar feel since it hasn't really changed all that much (which is both a good and bad thing). The sole reason I use BiteSMS is for quick reply and I like how it integrates with Lockinfo. The QR window comes up and can be closed without marking the message as read and any typed message remains. However I don't like having to have SBSetting installed along with Lockinfo AND BiteSMS. Seems like too many things that ISX does by itself. I like the customizability of Lockinfo, but I end up just having it similar to how ISX is by default anyways aha,

. Though I would prefer if ISX would adopt the ability to change what widgets are viewable in each screen, since having the clock/ticker widget is kind of useless in the normal notification center.
*sigh*
Typing this made me switch back to ISX. Had been using Lockinfo the last week or so. Seems I'll never decide
edit: for battery life, it really depends on the settings. Both have the potential to slaughter your battery if the refresh intervals for the plugins are set to low values. I set mine to high enough values that its basically manual refreshing whenever I want it to.