Phil & Ted's Lobster

[Boggler]

I'm looking for a high chair that won't take up too much room in the
Kitchen and have come accross the phil and teds lobster portable seat. It looks great and would be ideal for our breakfast bar/ table. Has anyone used one? Are they sturdy, safe, easy to,fit etc. our breakfast bar/table is made of granite so very sturdy and about 2" thick - instructions say it would fit so I just need to get some MN opinions before I part with cash.