I started posting on this forum basically in order to contribute to this conversation, since there doesn't seem to be a lot of up-to-date info on the reputation and reliability of Rhino Seeds. Given the mixed reviews, I was hesitant to purchase from them, but they also had what seemed to be the last pack of Nirvana/Sativa Seeds' Full Moon for sale anywhere on the planet, so I was willing to give them a try. Their customer service was prompt in responding to my questions (yes, they did in fact still have the strain for sale!), and shipping was decently swift from the UK to my location in the US (about ten days total upon their receipt of my cash).
I was scrupulous about sending the cash registered mail as they instructed, which wasn't cheap, but I really wanted these seeds, and was also curious about whether they would come through, and didn't want to give any excuses for failure to deliver. The beans arrived in the original sealed breeder's pack, so I'm fairly certain I got what I paid for. The price was admittedly not the best in comparison to other retailers' listed prices (Attitude/Seedsman, etc.), but once again, they were the only outfit that had what I wanted, so I was willing to give it a shot. I've got the seeds soaking in water now; since this is a discontinued strain, I'm unsure of their age and viability, but my fingers are crossed and I'm hoping for the best.
Your mileage may vary, of course, but on the basis of my experience, I would consider ordering from Rhino Seeds again if they had a strain I really wanted and I were unable to source it elsewhere.