Inflated size: 66cm (H) x 170cm (Dia.)
Last year I got the Miami style spa for $550ish which is 180cm diameter. We use it all the time with two adults and a child (the Miami spa is rated for four adults but that would be very uncomfortable). This is not hugely smaller so for a couple this is a pretty solid buy in my opinion. It's one of my favourite purchases.
This is a good buy, they dont tend to last that long, I have had a couple, usually last a year or 2 or 3 before some issue appears - but they are cheap enough to not worry to much and just get a new one.
They are good if you want to put on a deck or something and not so sure about the weight of a normal spa. They do use quite a bit of power thou - $1-200 a month alone in the cold months with regular usage. Thats worth it for me thou.