Lie flat car seats - worth the cost?

[Needmorehands]

Expecting baby mid May and have managed to get most things from FB/ebay but I don't want a 2nd hand car seat, tempted by the Kiddy evolution for the lie flat function, and it takes a baby up to slightly taller than standard, but they are very expensive.
Is it only worth it for the Evoluna which can also lie flat when its being a car seat, rather than just when its out of the car, but of course you pay more for the privilege!
Not planning to reuse it for any more DC, so reluctant to spend a fortune on something it will grow out of quite quickly, but which is very important for their safety...

We have the Kiddy one that lies flat out of the car but not in the car. I do like it a lot, it looks really nice and has a great hood, and it fits on a travel system and lies flat on there so you can have baby in supermarket and be a bit less anxious about them being in the car seat.

Downsides - it is massive in the car so make sure you can fit it in! When you lie it flat it clicks very loudly and this sometimes disturbs sleeping baby leading to rage on everyone's part. When it lies flat the straps go a bit too tight around baby so we would end up unfastening the straps when lying baby flat and just making sure he didn't fall out, then doing them back up if we sat it back up.

We are using it for a 2nd DC so feel we have good value from it and we've liked it but if you're only have 1 I can see that it is expensive.

We have the evoluna and it was a godsend. DS hated the car, so when on long journeys (both sets of parents live 2+ hrs away), if he eventually stopped screaming and fell asleep, it meant we didn't have to stop! We never used it on the pram though as DS hated being put down.