First, let me state that I am going to describe my very first contact with Spice, so unfortunately I cannot comment with regards to how different products compare against each other, but for what it's worth, here's my preliminary take on the brand.
I received some Spice Arctic Synergy a couple of days ago, and I have been exploring it eagerly since then. I would say that it's very similar to cannabis in terms of the high it produces, although there seems to be something missing that I can't quite put my finger on. I found the body high to be almost identical to that of weed, and the general "stonedness" is very similar also. Listening to music on it is wonderful. I did however have trouble enjoying watching a movie/tv show as much as I do on cannabis. There was also something missing in terms of euphoria (if that's the right term to use here), in that it was lacking the forceful giggle element of cannabis. I was able to watch family guy and american dad with a straight face, for example, which almost never happens to me on weed.
At first, the psychedelic elements also seemed to be missing, but pushing the dose eventually did the trick, conjuring up nice visuals, creativity, deep thinking, and increased awareness of senses, the effects that I enjoy the most about weed. Also, I noticed no hint of anxiety even at high doses. Actually I felt even less anxious than I usually feel on cannabis. Just thought I'd mention this - it seems that many people are complaining about anxiety on Spice products, but this doesn't seem to always be the case. Perhaps some of these products are more prone to inducing anxiety than others, seeing how the synthetic cannabinoids are present in varying proportions between different spice (and other similar) products. Some people even claim the same product can have different mixture of cannabinoids added to each batch, but I have never seen any evidence to support that.
Another thing worth mentioning is that the potency of these products (at least the Arctic variety) could be much higher. I needed to smoke several bowls of it to get properly stoned. Given that I had practically no cannabinoid tolerance to speak of, it would have probably only taken a decent toke or two of decent quality bud to get me to a similar level. I ended up smoking about a gram in one evening to keep myself high enough - a gram of quality bud would have probably lasted me a week. So, economically, not a very good deal (Spice only costs about half the price of weed where I live).
To those who have tried Spice Diamond, is it a lot more potent compared to the other varieties, or just slightly? I am trying to figure out if it's worth pursuing any further. Would you guys say that if Diamond doesn't do it for me (ie provide a worthy and at least financially equivalent alternative for cannabis), no product will?