Hmm....my previous FD job, even though we were EMTs on BLS ambulance we carried Zoll E-Series monitors on the ambulance (the medics were all FF/PMs on dual medic engines that acted as squads, If we showed up on scene first, or at the same time as the engine, or as they're pulling the gear out they could see us pulling up, we'd bring in the monitor and BLS bag that included O2 tank, airway and trauma supplies and the monitor, the medics would just grab the drug box, they'd only grab the engine monitor if we weren't in sight when they went on scene)....roundabout way of saying I got to know the E series lol. Now County FD we run with uses the X-series, but our medics use the LP15 (which I got a class on when I did the 1&1 training to work on a medic unit at our company), but one of the smaller city FD's still uses older LP12s ha.
While I was introduced to the Zolls first, I found the LPs easier to use from an EMT perspective without much in the way of training (or just observing their medics using a couple times) as all the controls are right there easy to use. The difference between the LP12 and LP15 is a lot less than the E to X series, the 12 just looks like an older 15 haha but seems more or less the same.
Maybe it was just that I got a lot more hands on the E-series than the X, but I feel the X is a little more complicated to use, and yeah, I really dislike the way the X prints off on the side, right into the equipment bag, seems like the County guys are always having paper jam issues on their Zolls vs the other fd doesn't have issues printing off their LP's. Although now that I think about it, their old LP12s seem a lot more sensitive to pt movement when trying to acquire a 12 lead that the X-series just doesn't quite seem to have that problem.
So yeah, from my limited experience, I'd say I'd prefer an LP over the Zoll right now, but it's funny, the LP15 is the monitor I have the least amount of experience on lol