Lailah Queen is the ultimate defensive skell when equipped with top level weapons and augments, Mastema White Reaper, on the other hand, can hit the skell damage cap, one-hitting Pharsis and two-hitting Telethia...takes a ridiculous amount of Ultrafauna Slayer augments, though. The Ares is amazing when you first get it, but has limitations that become apparent when fighting the superbosses.