By Justin Harper Published: 3:07PM GMT 11 Mar 2010  This week, Barclays and Halifax have both launched top-rated Isas as savers rush to meet the April 5 deadline and use their £3,600 cash allowance (this has already risen to £5,100 for those over the age of 50 and will do so for all savers in the new tax year).  Saving experts have been waiting for Barclays to launch its cash Isa for this tax year as it is traditionally one of the most competitive tax-free savings products. However, the downside is that Barclays, unlike Halifax, does not accept Isa transfers from previous years.  Barclays is launching two new Isa accounts. The first is a new issue of its Golden Isa, paying 3.06pc including a 1pc bonus for 12 months. Savers can invest this year's allowance into the cash Isa, but it doesn't accept transfers in.  Its rival Halifax is launching its Isa Direct Reward. The account pays 2.6pc for the first 12 months providing savers maintain a balance of at least £1,000 during that time and make no more than four withdrawals. After 12 months the account reverts to the Isa Saver Direct account, currently paying 0.50pc. The account accepts transfers in and savers can make additional deposits during the year, provided they don't exceed the annual cash Isa allowance.  Flavia Palacios Umana, head of Halifax saving products, said: "The Halifax Isa Direct Reward allows both new Isa accounts and transfers of previous tax year savings so customers can make the most of the great 2.6pc rate on all their Isa balances. The rate is also variable, which means that should the Bank Rate increase, so will the amount of interest received."  But Rachel Thrussell, at money researchers moneyfacts.co.uk, said: "These are both good rates, but come with strings attached in the form of bonuses applied for just one year. So once this ends, make sure you move your money out to a better deal."  She also advised savers to look at Isas that accept transfers. Given the huge amounts people may have already built up in tax-free savings it makes sense to find a better home for them – not just this year's allowance.  Other new deals are being offered by Derbyshire Building Society, which has recently increased the rate on offer for its two-year, fixed-rate Isa. The account matures on April 30 2012 and pays 3.25pc. It can be run in the branch or by post and savers can invest from £100 into the account, which accepts transfers in. You can still access your money during the term, subject to a loss of 120 days' interest.  Savers looking to maximise their Isa balances are being offered best-buy rates from Principality Building Society. The society has this week launched its five-year, fixed-rate Isa paying 4.5pc. Savers can invest upwards of £3,600 into the Isa. Transfers in are accepted, but savers must notify the provider on account opening. Access is available on closure only and will be subject to a loss of 360 days' interest.  Moneysupermarket.com said that asic-rate taxpayers who have saved the full allowance in the average cash Isa every year since Isa were first introduced in 1999 will be £2,900 better off than a saver who has not used their allowance and saved in a like for like basic easy access account instead.  The difference is even more marked for higher-rate taxpayers – those who have saved diligently within an ISA wrapper will have earned interest of £12,622 compared to someone who has saved in a basic easy access account who will have just over half of that amount, £7,030. Anyone invested fully into the top paying Isas would have a total pot of over £46,000 as a result.  Kevin Mountford at moneysupermarket.com said: "The tax free interest, particularly for higher tax rate payers is worth smiling about."  Whichever Isa you go for, make sure you don't leave it to the last minute and risk missing the April 5 deadline – especially this year as it falls over Easter. April 5 is actually Easter Monday, so some providers may not be open for business. And given the Good Friday (April 2) is a public holiday followed by a weekend many providers may only accept Isa applications on Thursday April 1 – so don't be an April Fool.  Find out more from Telegraph Fund Supermarket
Two major high street banks have joined the fray to grab a slice of the cash    Isa market before the end of the tax year.