Baytril is enrofloxacin, an antibiotic which happens to be known for causing cartilage problems in animals at rapid growth phase (ie growing quickly). It is a broad spectrum bacteriocidal antibiotic with good penetration in many areas. It is banned for use in food producing animals in Canada (except maybe as a turkey egg dip or something like that but I don't do birds) so I've never used it in cattle. I personally think it was a mistake to licence it for cattle in the US, but that's my opinion.
Micotil is tilmicosin, a long acting antibiotic which is given subcutaneously at the rate of 1.5cc/100lbs in cattle over about 200 lbs, 3cc/100lbs under about 200lbs. It is especially good at pneumonia, and is bacteriocidal and also gets mycoplasma. It is licenced for use in cattle and has widely known safety data in them. Don't use in other species--it can cause anaphalactic reactions and death.
If you want to know which is better, likely Nuflor (florfenicol) but you didn't ask...