I would consider our company mid-sized.  We use iCIMS and it serves our needs and offers features that we haven't chosen to utilize yet.  I find some aspects a little "clunky" but overall does the job and offers advanced features.

I agree with Grace - we completed an RFP several times when we were both a large and mid-sized company and iCIMS was the best choice for us. We've had it for almost 3 years now and have no complaints especially compared to some of the big box ones we used in the past. Very affordable as well.

Ann -- I've heard positive things about iCIMS, the vendor mentioned here by Grace.  By way of full disclosure, my organization offers an ATS (HireCentric) targeted toward mid-sized organizations.  If you'd like to see an overview of our offering at any point, please let me know and I'd be happy to help you with that.  Ultimately, which option is best for your group likely will depend on the features/functionality you need, balanced with what your budget will allow.  Good luck!

We have around 175 employees, and we love Newton!

SmartRecruiters is the bomb.com! They have free options and options you can purchase. Definitely do a demo with them!