I was using this one: http://www.fallout3nexus.com/downloads/file.php?id=97

But it hasn't been updated in awhile and I'm not sure if it's compatible with Broken Steel.

I've thought about using Arwen's, but I'd like to get some community input on this.

I have used Arwen's Leveling Mod and loved it. If you don't have any other mods that slow down leveling then Arwen's is the way to go.

FWE comes to mind, you can config how slow you level to

I've been using something called Fallout3BetterPaceMod. It reducecs xp for most stuff but slightly increases it for finding new locations, so it encourages exploration.
I can't seem to find it on the nexus though. Not sure exactly where I got it, but I like it.

The one you are using should be compatible I would think. If you are unsure you can use the Lite version which just changes the xp bump base, though the full version should work fine. Broken Steel just changes the level cap I don't believe it alters any of the things changed in the mod you are using. You can use FO3edit to check for compatibility. As far as I know FWE has the mod you are using merged into it (though it may be modified).

I've heard FWE is popular mod, but I looked into it and I don't think it's my style. I try to stay close to the classics, and FWE pushes it more toward the FPS side of things.
Speaking of Broken Steel's extended level cap, have you guys found it to be sufficient, or would you recommend sticking with a level cap workaround mod?

FOOK2 v1.1+ has an optional leveling feature with a grip of options including the scaling of quest XP to match your preference, which really makes altering the desired XP percentage more impactive.

I've used the mod you have and it works with BS just fine. I liked it. There's a newer mod, called Experience Control that was released pretty recently that I'm planning to try, but haven't yet, that is more flexible

http://www.fallout3nexus.com/downloads/file.php?id=10597

That you might want to check out.

The mod you linked in OP is compatible with Broken Steel. The mod changes one global variable, and thus its changes apply to anything that you load into your game.

I use Experience Control. You can go into a lot of detail with settings if that's what you want or just alter one setting to adjust the amount of xp you get off everything. You get the book after you exit the vault and can change things at any time, although I don't change the xp bumpbase I think its called, just the percentage of xp and the hard difficulty level of the critters/npc's.

I forgot to mention that I am currently using FWE. I was using both Arwen's and FWE at the same time and go into a bit of trouble where I was no longer leveling. So, watch what mods you combine. Like I said, I loved Arwen's mod when I was using it. But am currently running FWE.

FWE and Arwen's are both big overhauls (despite the deceivingly small filesize of Arwen's) which are never supposed to be used together.

I use http://www.fallout3nexus.com/downloads/file.php?id=2812 which offers a very simple and effective solution. I highly recommend the FOSE version. I've not looked back since.

Yeah, that's the one I use and it's seems more straightforward compared to some of the others that tweak this or that.