Consider what you're saving money for. You may want to use more than one savings account, depending on what you want to do with your money.
A Lifetime ISA is designed to help you towards saving to buy your first home, or to save for retirement (though it's not necessarily a good thing to use for the latter). You are limited to only paying in £4,000/year into a LISA, considerably less than the standard yearly ISA limit. However, you recieve a 25% bonus on any payments you make from the government. If you're saving for a house a LISA may be useful to you.
Most cash ISAs are essentially the same just with different restrictions on what you can withdraw, and with different payouts of course. Working out which one is best really comes down to number crunching, based on how much you're planning to pay in, and when.
Have a look at interest rates on current accounts too. Some of them offer you better interest than ISAs do and if your savings amounts are relatively small, you won't be taxed on the interest anyway.
If you’re willing to leave your money in the ISA for at least 5 years then you can look at stocks and shares ISAs and investing in multi manager mutual funds. In that case you can generally look at an amortised 10% interest annually
If I'm honest, this thread has made me more confused on ISA's (and related savings) than before!! I'm really not sure which is best for me now.
Help to Buy (ISA) if you're looking to buy a house in the medium - long term future although I'm not sure if they are only available in Scotland?
For every £200 that you save (maximum monthly deposit, although you can put in up to £1,200 in the first month), the Government will put in £50 (25%) up to a maximum of £3,000.
Some lenders allow you to withdraw at any time without charge however you obviously won't get your government bonus on this amount. And to get the bonus you must be putting the whole amount towards the deposit for a property.