LSA is actually a wonderful psychedelic, one of my favourites in fact. I used it a fair amount a couple of years back and I found it to provide the most natural feeling, jovial, psychedelic headspace. Discovering that my friends and I could trip to that intensity from some seeds that we could buy from a DIY store down the road was a revelation.
The headspace is quite dreamy, and there is much synaesthsia, and especially music appreciation and euphoria. The body high is incredible, and visuals are outstanding. Marked colour enhancement, fractals, warping, all the things you would expect from a good psychedelic. It is great for drifting off in to closed eye mindscapes, and the somewhat sedate dreamy quality actually lends itself to that. But it is equally great with eyes open, roaming outdoors experiencing the awesome beatuy of nature.
The visuals, synaesthesia, euphoria, music enhancement, and loving headspace could definitely be compared to LSD, but in my opinion the empathogenesis is even greater on LSA. You can feel that the two compounds share the same ergoloid lineage, in both the body and the mind. LSA has a more lightheaded and relaxed feel, whereas LSD is quite energized and pumped up. LSA has provided me with probably the best afterglows I've ever experienced from a psychedelic, with marked colour enhancement and euphoria persisting for a good few days afterwards. Wonderful stuff.
In terms of intensity, 350-400 morning glory seeds has had me tripping as hard as 5 hits of good LSD, though the potency can vary somewhat. Easily as deep and worthy as LSD, if not more so due to the intense empathogenesis and mellowness.