The primer smoothes on very easily and a little goes a long way. I tend to apply it in small dots to my forehead, chin and cheeks and blend until my face is covered. It doesn't feel greasy or oily at all on application, but if I touch my face I can feel that it is there. It doesn't seem to sink in as such, rather it just sits as a layer on top of the skin. That said, it is not a product that feels thick or heavy once it's on.
Unlike some other primers this one doesn't claim to moisturise and having dry skin I can vouch for the fact that it doesn't add moisture. One thing it does claim to do is minimise the appearance of enlarged pores. I don't really suffer too badly from enlarged pores except one or two around my nose and to be completely truthful I don't think this gel did anything to help them look smaller.
I find that my foundation seems to go on much more smoothly when I have applied this primer first. I don't particularly notice any difference to how my skin looks when I have applied this, but it definitely helps with longevity. I'd say I probably get up to three or four hours extra wear from my foundation having applied this, which may not sound like a lot but can mean the difference between having to reapply my makeup or not.
A 15ml tube of this primer costs £4.99 and is only available from Boots. 15ml may not seem like a huge amount but only a little bit is needed per use, so it does last. I think £4.99 is a really good price as the Smashbox one - which I feel this is similar to - costs closer to £25 for 30ml which obviously works out much more expensive.
Overall I'm pleased with this primer and I think I would buy it again. I don't think it is perfect - it doesn't seem to make much difference to the appearance of my skin - but it does help it feel much better to the touch and more importantly keeps my foundation on longer which is what I wanted it for.