Let me first say both are awesome mods. However, lr cartos are not a good idea at 5v IMO unless your ok with the possibility of a burnt taste. They are both different animals as well. Bottom feeder with a smaller footprint vs 5v semi tube mod. Rob and Jay are both good suppliers and I'm sure they will back their product if anything were to fail. As much as I like the glv-2, it just doesn't get easier than having a
juice fed
device with a lr atty/carto at 3.7v. With an lr atty I get pretty much the same feeling as 5v. You can even drip into the REOs cash cup if you want to try new flavors. I'm not a carto guy, but there are people who use there REOs with a carto and love it. I sound like a REO fanboy, but I'm just so impressed with them. I am no way trying to put down glv 2, but you said I could share my story

When it comes to pocket friendliness I would have to say the REO mini wins again. Jeez it's really sad that my urge to vape has ceased and that I will have to give up my own REOs up soon. Their just so darn awesome it sad to see them go.
Anyways I hope this helps. Hopefully someone who has tried both will chime in.