Mcintosh c-2300, is it worth the money?

I'm new to high end hi-fi, but learning. I recently purchased a pair of mc-501's. I plan on buying a tube preamp. I like the aesthetics of the c2300, but don't know much about it. I'm also looking at audio research sp-10, because everything I've read about them is positive. I'm trying to stay under $5000, new or used. Aesthetics are not as important to me as sound quality, but would like to have both. Any ideas?
Had a new C2300 in my system for awhile. It was far and away the most musical, natural pre-amp I've heard. The dual MC/MM inputs were especially nice as I have two tables. Build quality is second to none. Downsides? It took forever to warm up (the main reason I traded it for a C50) and it didn't especially like electronic music (not a real problem for me, but some of my stuff wasn't as listenable as I might have liked).

The SP-10 is also a truly sweet piece. Honestly, you wouldn't go wrong with either one.
I have spent a fair amount of time comparing McIntosh and Audio Research equipment through the years. I too like the McIntosh aesthetics, but for critical listening Audio Research is typically the hands-down winner.
I have owned a SP10 MKII and I currently own a C2300. The SP10 is a high maintenance unit and it eats tubes! If you don't mind spending listening sessions trouble shooting it is a descent sounding unit, but the C2300 sounds every bit as good if not better and it is extremely reliable and QUIET! You also know it will work with your amps! I am constantly amazed how many people take a crap shoot hoping their amp and preamp will work well with one another. Don't do it! Buy the C2300 and be happy! That's my opinion anyway! Good luck.
I think ARC makes some great sounding gear but in your case, I don't see why you wouldn't get great results going with the C2300. McIntosh usually picks dealers that give excellent customer service. Your dealer may be willing to lend you one of their units, or even bring one to your home and set it up for you.

If for some reason you don't like the C2300, you may want to look at an Aesthetix Calipso. Its within your budget, sounds great and is built extremely well. I have one and am very happy with it.
Thanks to all that responded. I will pair my amps up with the 2300
If you get the C2300, replace the cheapo chinese 12ax7 with Teles ribbed plates. They made a HUGE improvement in the C2200. Can't believe it was the same pre.