GNex pluses: unlocked BL, HD screen, ICS OTB, OMAP 4460, camera, NFC, updates from Google, most likely a big dev'r community
GNex "minuses" [as in, i'll need to see real world testing to address these concerns]: form factor/aesthetics (personal preference), no sdcard, build quality, call quality, LTE connectivity, battery life (nothing proven yet, but these have been issues with Sammy devices before)
RAZR pluses: build quality, aesthetics, call quality (Moto's history on these), battery, storage (16 gb on board, 32 gb expandable), rooted already, will get ICS quickly, improved screen (still not true HD, but probly not noticeable and still a vast improvement over prior devices), thin and light yet sturdy, some nice new features (MotoCast/MotoActv)
RAZR "minuses": encrypted BL, Blur (but can be removed with root), "only" OMAP 4430 (altho, clocked at 1.2 just like GNex), camera (don't know if been improved/fixed), no ICS OTB, non-removable battery, no NFC
if hacking and roming is a big issue for you, you're probably best served by going with the GNex - the dev'rs are just salivating over the chance of getting ahold of this device. for me, rom'ing isn't a huge issue any more. the NEED to rom has been diminished because of all the advancements in speed, as well as the improvements to the OS. but, like you, i don't like the idea of not being able to hack my own phone, if i want. however, i'm still undecided as to whether that is enough to sway me toward the GNex. i'm just gonna wait until both devices are out, test each one, and read other users' opinions of both before i make a decision.
the great thing is, you really can't go "wrong" with either device - they're both gonna be monsters!