Chevy Equinox / GMC Terrain - I have a GMC Acadia and I am a fan. I have favored Ford in the past and took a hard look at the Explorer before deciding on the Acadia. We liked the ride of the Acadia better but the biggest factor was that the Traverse/Acadia/Enclave were among the safest SUV's out there (I did a bunch of research including pulling deaths per accident etc). The Chevy Traverse, GMC Acadia and Buick Enclave are all on the same frame and largely the same vehicle with differences in styling, packages and the 'details'. The Acadia and Terrain are very similar with the Terrain being a bit smaller. I was looking at them last night (I took the Acadia in for service) and I really hated the rear space in the terrain (basically there was none unless you put the back seats down). If you like the Terrain I would say look at the Acadia as well. But you actually might like the Buick Enclave (I think the Buick version of Terrain is Encore) as they are a kick up on the luxury side over GMC where as the Chevy versions is a kick down from both. For my Acadia- as long as you don't plan on towing anything then you are good to go. It would be crap if towing. The power is 'sufficient' but not exciting but if you were towing anything that weighed anything it would not end well. My only real complaint is the hooks for hanging dry cleaning. They are on the back row which is a bleepity bleep to get to from either the back door or the hatch. Makes no sense but if that it my biggest complaint then I think I made a good purchase decision.
I would say the Explorer is not a bad option. It came close for us. I have friends who have them and no issues.
Jeep Grand Cherokee - I would not consider. Consistently the lowest ratings on vehicles when I look at reports are the Jeep family of vehicles with the only real exception being the Wrangler types. I have been tempted to look in the past because there were things I liked about them and they were offering good incentives but when I dig into some research then reliability always seems to be low and there is a lot written about the overall quality being low.