I had very slow progress with Zhang's, my symptoms slowly improved until about 4 months when I started to feel some of my symptoms coming back. When I stopped after 6 months to check my CD-57 most of my symptoms returned.
Buhner's core protocol consist of Cat's Claw (plain, not TOA free, so it's cheaper), Reseratrol, and Andrographis. I just started my 4th week today and am tolerating it well. You can read more in his book Healing Lyme, I got my copy from Amazon.com.
I'll probably add the grapefruit extract after I taper back down the doses (after 2 months), I have enough pills to swallow right now, and I want to see how the core protocol works by itself. I did have a pretty good herx on my 5th day. My herxs were mild while on Zhang's.
Hope this helps, KO
P.S. Buhner's core protocol will still be about 1/2 the price of Zhang's and once I taper down the dose it will be even less expensive. I have a coupon good for $5 off your first order from iherb if you decide to order supplements. Let me know and I'll give it to you.