While the SL8 is a neat and accurate rifle ( I considered getting one myself). I would seriously consider looking at the Swiss Arms Black Target (flat top) for the role you're planning on using this rifle for.
The flat top makes it very easy to mount larger designated marksmen/varmint style scopes. With the PE-90 target Swiss arms rifle, scope mounting is easier and in my opinion probably a lot better for keeping zero. This is based on experience with the PE-90 and internet talk about the SL-8 (So it could very well be wrong).
SL-8 $2144.00 (Wolverine)
PE-90 $2800.00 Note the price has been dropped recently on these from the $3000 to $2800. (The shooting edge, Wolverine also sells these but the price hasn't been updated on their website)
Difference: $656.00
Now add in that you'll need a bipod for the SL-8 and that's another $130 (not including the cost of the stud and work to install it). So now you're down to a difference of $526.
Comparison at a glance:
PE-90: Built in bipod, steel receiver, decent trigger out of box, fantastic folding stock, military style barrel with the flash hider, scope rail attaches directly to a metal receiver. Excellent fit/finish. Easy no tools required take down. Designed for 63 grain bullets. 1/10 twist I believe (double check this). AK reliability. Ambi safety.
Criticism: Heavy, expensive. Ergonomics are a bit off (still very useable just not perfect). Ak bolt on the wrong side for right handers, AK style mag release, Cost of magzines.
SL-8: Lots of polymer for weight reduction, thumb hole grip (Some like, some don't), heavier contour barrel, 1/7 twist I believe for heavier 69 grain .223, should also shoot 62 grain. I've heard various things about the trigger. It's supposed to be about 3.5 pounds. Some really like it, others don't. Milleage varies I guess. Considered to be fairly accurate.
Criticism: The stock. A lot of people don't seem to like the thumbhole and convert these to G36 clones right away. There has been a lot of talk on the internet about cracking polymer receivers on these firearms. That could be a very big concern. Of course that may have been addressed by HK. HK service/views towards civilian ownership hasn't been good in the past. Wolverine however has an excellent reputation, so that isn't really a problem.
Bulky. This firearm while looking cool and futuristic also tends to look a bit bulky, no doubt from the thumhole stock and rail system. I personsonlly don't like the looks but that's an individual thing.
When you factor in that the real cost difference is about $526 dollars. You're really in the market for either one. Also consider that you can get quality optics for less than the $1500 you were willing to spend.
For Scopes I'd recommend the Zeiss Conquest as the best bang for the buck in the higher end scope range. You should be able to find one without even trying in the $1100 range with 6.5-20x 50mm (Shop around and you can probably get it for a bit less, or buy one second hand, I've seen $950 for NIB second hand). You can cut costs a bit if you don't need that much magnification.
Now here's the budget entry that I would probably recommend. Ruger Mini Target $980 rifle. Optics: Falcon Menace 4-14 FPF 44mm $385, or Burris, Bushnell elite 4200 (I don't really like this one myself), etc etc. Accuracy is very good, non restricted, very reliable and piston system.
Cons: trigger needs work from what I've read, and it doesn't have the uber cool black rifle look. Although it is nice looking in it's own weird way. With a decent scope (not top notch though) you can be out shooting this for the same cost $1500 you were willing to spend on the scope alone.
This may be a good option if you're waiting for the Bush Master ACR / Magpull Masada. Which may be the next big thing if we get them next year.
Something to consider.
Let us know what you decide, and why.