How do their offerings compare? Are they reliable unlike the mazda diesel?
The Mazda diesel only had issues back in 2012 in the CX-5 with oil dilution when it was first launched. This has long been fixed with a software upgrade and a new dipstick. The same engine was used in the Mazda6 which never had the issue though I don't know which used it first. I can't provide you with how the other rival's Diesel compare in terms of reliability. I've not owned or driven them.
The Mazda Diesel more often than not comes out on top in reviews. Here are some Diesel SUV comparison tests you can read for yourself. 1, 2, 3 since you can't find out yourself for the sake of curiousness.