Rit, I do some tuning/hacks (primitive tuning) for a GM TPI engine from the 90's and used TunerPro with my laptop and USB connection to the ECM. If you're just wanting to look at data, bluetooth is the way to go. Those USB wires annoy me - and the data port for the Terrain is right by the Emergency Brake (can be tangled up with your foot, and yes,
I actually use the emergency brake, ha).
BUT, if you think you'll want to do some editing, then the USB connection would likely be better.
Something else to think about - the cheap bluetooth ELM327 dongles have very slow data transmitting rates (and transmits less data simultaneously - affects data logging). The price hike is because the higher end models transmit more sensor data simultaneously with faster refresh rates. If you're just checking out some temperature readings or trouble codes, sure, the cheaper ones would be good enough. Trying to watch for misfires, knock retard, timing, etc - faster data is better. And often, the cheap USB ELM327 transmit data faster than the bluetooth ELM327. If I were trying to stay cheap, I might opt for the USB models in hopes of decent data refresh rates.
If I already had a USB interface tool, I'd keep using it (like rbarrios is). Since I didn't have one for an OBD II system, my wife spoiled me.
And, for me, it feel disturbing to "trust" a $10 part to interface with a $30k vehicle... Don't want it to mistakenly set a parameter to cause the airbags to blow when you change your HVAC system from heat to defrost, haha. (Don't think this is possible, but... don't want to find out the wrong way.)
I have no experience with the cheap ELM327, so I can't be much help here. Hope someone else can share their experiences?
Rit, in your case, it seems you lucked out with a reliable 4 cylinder from 2010. So you might get lucky with the cheap bluetooth ELM327.
Share your thoughts in the New Year after you've played with yours??