@Mollymarvelous70 new build prices are inflated, but then you've got to think everything you're getting is brand new: carpets, boiler, appliances, windows, roof etc. Barring getting the house set up the maintenance will be minimal in the short to medium term and of course you have a warranty if there is a problem. Banks wouldn't lend if the house was a risky investment, although many banks will only lend a minimum of 90% LTV and won't take the risk with a 95% LTV (even in normal times)
If the home is a long term investment any depreciation should be slight, if at all considering south east, if you fix for 5 years it's very unlikely (not that anyone can predict at the moment of course) that the house will be worth less than what you paid for, but the good thing about help to buy is the government is taking 20% of the risk. I'd rather take out a help to buy loan with 75% LTV mortgage right now than a 90% LTV mortgage.
If it's a shorter term investment then no I wouldn't recommend a new build, unless your area is very strong and they hold their value well, and I'd be a bit more apprehensive about the London scheme where the loan is much larger but they really to seem to inflate the prices (from what I've read).
Similarly we didn't want to impact our lifestyle too much, we already have children. HTB is getting us into our forever home, our mortgage payments are reasonable with the 75% LTV interest rate and HTB loan and I am relatively confident we will be able to remortgage the loan out in 5 years, but worse case if we don't we have to pay interest on it so it wouldn't be the worst thing but would rather pay off a larger mortgage if possible.
That's just my interpretation for a few reasons it suits us but it won't suit everyone, I recommend talking to a broker to really explain all the ins and outs to you. It could be a really good option but you just need to be aware of the downsides, as it isn't perfect. It isn't free money sadly!
And it's always having in the back of your mind interest rates can (and will) only go up, so be careful if borrowing up to the max, think about childcare, if you want another child etc. That is true of any purchase of course.