That Mongoose looks like it hasn't been made in a while, so it's an older bike. Would probably be my last choice.
The HRXC and Komodo are two different animals. The HRXC is the more race-y of the two Hardrock models (Hardrock and Hardrock XC, Specialized entry level hardtails). The Komodo is a slack all-mountain hardtail, with the newer models being burlier than the older models.

So what do you want the bike for? Are you going to be riding it around your neighborhood? Fire roads? Singletrack with a lot of climbing? Go with the HRXC. Or are you looking for more of a playbike to throw around and jump? Don't get me wrong, the HRXC will take some abuse too, but the Komodo is made for that. Similarly, the Komodo can climb just fine, but it's not the billy goat an XC bike will be.

And more importantly, are they both your size?