I'm in the same boat
I'm saving up for a P30 when I get home (planning to make the jump from a 9mm M&P to a .40 P30) and I've been asking the same question. I did a lot of research on the HKpro forum. I have very little actual experience with the P30, but here's what I learned in my research so far:
The consensus seemed to be that it boils down to personal preference and how much you can practice. Threads like
http://www.hkpro.com/forum/hk-handgun-talk/149614-why-lem.html were very helpful (They get sidetracked on pages 3 & 4. After reading the first few posts, go straight to page 5, post #43 for the most-helpful input.)
Both designs have pros and cons. I'm really torn between them. I've shot both DA/SA and striker-fired pistols, so I could go either way. In general I like the idea of a consistent trigger pull, but I remember not being too impressed by the LEM I dry-fired in the store (I remember liking the Sig DAK better, but it's been a long time). For me, it might come down to what's available--I've only ever seen one LEM H&K in any store, and I've never been able to shoot an LEM, only DA/SAs (P30 & USPc). Not keen on buying something I've never been able to test-drive.
The thing that struck me most is that whichever you choose, you'll probably have to spend some additional money to get the trigger the way you want it. It sucks to spend extra money to "fix" a pistol that costs $900 to start with, but them's the breaks. If you already own a 1911, you're probably used to it.
For the LEM, you can only buy the V2 "heavy" version (7.4 pounds). This gives you a higher pull weight than Glock, XD, M&P, etc, and with more take-up. To get the V1 "light" LEM (~5 lbs) you need to buy and install a different spring. (It's up to you to decide if it's a good idea to have a light trigger pull on a carry weapon. Some people choose the P30S to mitigate this risk, other insist the long trigger pull is adequate safety in itself.)
A lot of people complain about the V3 (DA/SA) trigger being long, heavy, and gritty. The one I shot didn't seem any worse than my M9, but for $70 + shipping, Bill Springfield at
www.triggerwork.net will shorten, lighten, and smoothen (OK, that's not a real word) the V3 trigger. Bruce Grey is also recommended for extensive/expensive trigger mods.
Apparently it is possible to convert a DA/SA P30 to LEM, but H&K doesn't endorse it (probably because it leaves the opening for the decocker exposed). So that's an option if you change your mind down the road.