I would say with the exception of the DAT, getting into dental school (DS) is actually harder than getting into medical school (MS).
For one, there are far fewer DS than there are MS. Now granted, there aren't as many people applying to DS than MS, but with that, there are fewer in state DS where the applicant gets an advantage. This leads to a much less generous waitlist for DS as well. I'm routinely surprised by the people who get nothing from DS schools on this site, would could have gotten into their state MD school.
Also, there are osteopathic schools which have grade replacement, (although they are making it harder to do every year) and to my knowledge, DS does not.
Also, many people use DS as a fallback to MS, and Admissions are aware of this and can spot this activity and shut people out.
While both tests are difficult, There is no comparison for the DAT to the MCAT. I say this with sincerity, and with respect to both professions: comparing the MCAT to the DAT is the equivalent of comparing running around a track 2 miles vs sprinting a 5K marathon the whole way like your life depends on it. The MCAT is the hardest non professional exam one can take. The MCAT is on a different planet compared to any other test out there. The DAT is difficult, but it is the equivalent of 2 really hard college finals stapled together. The MCAT is a test on everything you have ever encountered in your life. Reading comprehension is crazy key to do well.
I took a diagnostic on both and scored a 486 (15%) on the MCAT and a 17 on the DAT, and this was without studying, Though the DAT was much more organic Chem heavy, which is my strength.
If I had to do it all over again (I was a late bloomer, low 3.0s in my science classes freshmen-Jr year of college, 3.9 my senior year) I would tell myself to major in a science subject, do well (3.5+), get a job at a dentist office, and go to dental school. The lifestyle is much better for a dentist (with the exception of dermatology) and dentists seem to be much happier overall. It's also only 4 years.