Im looking for a DD/DTS amp for about £250. Ive seen the denon AVR 1601 for £230, which is £70 off the normal price. Also the 1801 is £60 more but what features does this have over the 1601? Im also thinking of a yamaha RXV596 and 496,Which are £260 and £230. I would be grateful for any opinions and recommendations of any of these amps. Thanks. Jon.