I have a SR4 H, SR4 HH, and an L-2000. Let me first say that you won't go wrong with either, but there are some pretty big differences.
The stingray is just a classic- perfect for rock and roll, funk, whatever. Big punch, loads of grit. I know the guy from Chevelle plays a stingray, and I think the BB bassist does as well (but I'm not sure). The stingray has a very pronounced low mid presence that will cut through any mix well. Most of them now come with the 3 band eq, which some (including myself) think doesn't sound quite as good as the older 2 band eq- the voicing is just different. To hear the 2 band version, listen to "Another on bites the dust" by Queen or anything of of Rage Against the Machine's first album. The stingray also has a slightly lower g string output, and this is in the preamp and intentional according to Sterling Ball. If you were to get a Stingray, I'd suggest spending the extra $150 (american) and get the HH version- has the same Stingray sound as well a variety of other sounds, including a pretty good jazz bass sound.
The L-2000, on the other hand, never quite took off the way it should have, IMO. Maybe poor marketing, maybe a lack of original appearance- I don't know. It is extraordinarily versatile, and if you go to the G&L forum and search there are some basic presets that have been posted to get a variety of tones, from P bass to Rickenbacker. It's 2 band eq is cut only, which takes a little getting used to. It has a more balanced mid presence, which sounds great. I think the Magnetic Field Design pickups in the L-2000 are incredible. Right now, the L-2000 is getting more use in my rotation, but it is also newer to me. The only artist I can think of off the top of my head that uses an L-2000 is the bassist from Dillinger Escape Plan.
Both necks are unfinished and play great. The stingray has a P bass width neck, and the L-2000 has both P and J width necks available.
Both are great for hard rock. They both have punch (stingray maybe a bit more) and growl (L-2000 has more). If I had to pick just one, I would probably get the L-2000. It can cop a pretty good stingray tone, but has so much more flexibility compared to the stingray (even the HH). Also, the overall tone is a bit more "balanced", for lack of a better word, than the stingray- the d and g strings sound a bit thicker, less "nasally" or "tinny" (to use adjectives I've read on TB to describe the ray). However, you can't go wrong with either. My guitarist actually loves my stingray more than the L-2000, and keeps pushing me to play it more, which is sometimes tough not to given the fact that, from a shear, shallow appearance perspective, nothing looks as cool as a Stingray, IMO.
