chorus pedals are just as subjective as OD's - maybe more so. I felt the need to reply to your post because Ttis is the first time I have seen anyone even mention the world "chorus"! (I am somewhat new around here, although...)
My personal advice - buy an old Ibanez CS-9 on eBay. If you wait, you can probably get one for around $50-$60. They sound great - small footprint - and you can get your money back on them anytime you want by selling them.
If you want to get something really awesome, and have the money to blow, I have four suggestions:
TC electronics - Thin but sweet - a very distinctive chorus
Fulltone Choralfange - Pristine, clean, and very tweakable (you may think this one sounds weak at home, but it cuts through like nobody's business live on stage with a band - don't ask me how this works, but it does!)
Analogman Clone Chorus - Rich and full, but too rich and full to some...
DLS Chorus/Vib - Very versitile - sounds incredible - but large footprint on your pedalboard...and digital (although it sounds very analog, I guess I am just a purist, or snob, depending on your point of view!)
I have also heard some good things about the Retro-Sonic chorus, but I have yet to hear one.
Ibanez BCL-Bi Mode chorus-I believe there are versions in the 9 and 10 series as well. 2 chorus circuits in one- one side is similar to a ce-2(warm and smooth), the other more like a EH clone(wobbly) they can be used together- each has seperate rate and depth. A little patience should yield one in the 50-75 range.
I have the retro-sonic. I love it, but it's a very specific sound. It's an exact duplicate of the boss CE-1 from the late 70's. very warm and round, and not as bright as my blue CE-2 from the early 80's. IMHO it sounds best when going through the front of the amp, as opposed to the loop. It's the same tone as heard on the 1st 2 Pretenders records (although I read somewhere that Honeyman-Scott used the MXR big yellow chorus). It's also the exact tone that can be heard from Alex Lifeson on Exit...Stage Left. Which makes sense, since he was using a CE-1.
+1 on the Chorus Ensemble. It's the only chorus I use, but the price puts it above the $100 mark. I tried about 500 pounds of chorus pedals before settling with the Retro-sonic. It's one of the rare cases of actually finding and remaining fully satisfied with a purchase. +1 Exit Stage Left. + 10 for that matter.
If you like chorus, I thought the Visual Sound H2O sounded really good and you get a kick-butt delay as well. I've seen them for $100-$120 on the used market.
All good suggestions above. And it's true, chorus is VERY subjective. for my ears, I tried the Boss ensamble and hated it. Tried the Dano and liked it, but the Marshall stole my heart. Lots of control over the exact sound, and does the leslie thing great. I have heard they can be noisy, but I myself have never had a problem. They add some top end, so if thats not what your after, go for something else (I wanted some top end so it worked for me). Mxr has a new RI chorus out there that might be of intrest, though I think it's over $100. The Marshall is cheaper than the Boss and is under $100. Oh, I also have a digitech x-series chorus that I did like, but it's a little too subtle for me though it is very warm with a lot of control. but it didnt do the leslie thing which is the main reason I use chorus. Still, I keep it around for different flavors and it's under $100 if I remember.
I don't think anyone's mentioned the MIJ Arion SCH-1. It's talked about most often for it's faux Leslie sounds (which don't do a whole lot for me), but it's a great sounding chorus unit usually available for well under $100. I'd never choose it over my Retro-Sonic or Medusa, but it delivers bang for the buck.
I bought a Boss CE-5 (chorus ensemble) quite a while back, not being sure what I'd think of it. It can go from thick warbly stuff to very mild. It has an effect level knob on it which many chorus pedals don't have, and so it's really really flexible. You can usually score one on eBay for the neighborhood of $50. Not a bad price on a really flexible pedal.
E H small clone.
i have one that i traded for in 1978 thats still going strong.(i did have keeley clean it a couple yrs ago) never played on the reissue but ive heard it was ok. does a real passable leslie for me, in fact i have been asked several times after a gig how i was doing the leslie. for chorus it sounds good but its limited for sure.
the reissues are cheap.
Pearl Chorus-4 knobs (adds a blend and delay knobs to the usual depth and rate)-very clean but warm. One of the few that won't suck all the life out of an acoustic. Usually well under $100.