I have just finished bulk processing the equivalent of 23, 36 exposure, 35mm rolls of E6 with the Arista 1 pint kit, recommended capability, 4, 36 exposure rolls, I plan on running another 10 rolls through it with an additional minute of developer time. The results are as good or better than any professional service I could have gotten at 1/10 or less the price. I am switching to the Kodak 5l however for the sole purpose of any incremental quality increase I will pay for, regardless if I can see it or not, especially if it's just cents a roll tacked onto 50 cents. It is peace of mind. I would not hesitate to use the Arista product again though.
My evaluation of the Unicolor C41 kit is similar if you exclude the God aweful Stabilizer, which is a disaster in my experience. I could have washed the negatives in sewer water and been better off. I surmise this will work better, I've ordered some Final Rinse to replace the stabilizer/muck they include.