Erm brief report here:
As I said I got some 5-IAI of the only vendor that seemed to have it.
On saturday I put 200mg into 8 bags of 25mg each as I was going out that night and didn't trust myself with it

I started off doing 50mg nasally, felt little or no effects, maybe slight placebo.
I then went out on a night out, consumed a lot alcohol (I know, probably not the best idea) and did 100mg more (at about 20 minute intervals). To be honest, I didn't get any euphoria or anything like that and it didn't seem to enhance my night at all. I had this down as write off and money down the drain...
However... I've just put 200mg into a glass of water, stirred it and drank it down and 30 minutes later.... I feel great :D
Not as strong as mephedrone, but definite stimulation, music seems an awful lot better and I'm generally in a great mood. Also got a massive urge to ring people and speak to people...
Seems like a very clean drug, I'm in total control and it's not as much of a 'dirty high' (if you know what I mean) as mephedrone.
I can't compare it to MDMA as I've never tried it, but I've tried Ecstacy on holiday and it feels similar - though probably don't want to dance as much.
On the downside... As I'm writing this I can sort of feel the mind effects wearing off but my mouths still chewing a bit and my legs still swinging (not really good) and it's not as good as it was 10 minutes ago, which could lead to over-consumption in a party like environment...
From what I've read, people have said it's like MDMA in the sense that you're coming up and it's like 'This is it, this is it!'... Then nothing...
Anyway, when more vendors get this in and I'm guessing it might be purer (?) then I'll most likely be doing this again.
Hope this was helpful anyway...