I have used a Tikka, Tikka Plus, Tikka XP and the BD Spot (which is what I have now).
The first two were great, and classics. The plus is an improvement on the standard Tikka, for no real weight gain, and is worth the few extra bucks. The XP I didnt overly like-I gave it away when I got the Spot. I found the XP a bit heavy on my head, and personally I didnt like the buttons. It was better for night nav and rogaining though than the Tikka Plus-although that is usually adequate for me. I used to rogaine for a couple of years with just a standard Tikka without any real hassles except for a couple of checkpoints...just means you have to navigate off the map and features for the last 150m or so, instead of spoting it earlier and using your in-built neural-network to choose the easiest path over the terrain for the final dash.
I love the Spot though. At first I didnt read the instructions and so I didnt quite understand the button and used to get frustrated with it (for about 10 hours of use), but once you work it out, its great. It has so many lighting levels. The 3 LEDs are great for close up work and map-reading...I usually keep them on the lowest setting. They are fine on that setting for watching your feet whilst walking aswell. The Big LED I absolutely love for long distance lighting...sure you can get way more powerful lights, but this things lasts an eternity, has nice even light, and I have found it great for flashing out Rogaine checkpoints from even about 150m away (which is more than far enough!). I've even used it Mountain Biking at night, though I was going relatively slow (I'm not that fast off-road on my bike).
I would really recommend the Spot. It does way more than the Tikka Plus, and is lighter and sits better on your head than the XP. Its also cheaper (in Aus at least).
I haven't used the EOS, though I have seen it in stores.
Oh yeah, I haven't had any trouble running the spot on Li-ion rechargeable batteries, and have also used it with Energizer lithium batteries with no problems.
Good luck with your choice (you really cant go wrong with any of those models so don't fret),