You already have an Arduino, why not use as an ISP, and if you are building other boards anyway, why not get a few extra 328's so you have asome chips to experiment with.
What can say the popular STK500 ISP do that a £2.88 chinese cant do?
Turns out the Arduino dons't want to work as a ISP for me!
So, is there really a need for a ISP if you can use the Arduino, and if so what one to pick with them ranging in price from £3 to £150+
The link you posted was to a £21.40 device, hardly £150.
Well, to start with you get a "supported" programmer with a large user base, that you can pretty much expect to work, not a "questionable" clone of a hack that will leave you and would-be helpers scratching their heads going "do you know which firmware version is running on that?"Then stk500 has switches, LEDs, numerous sockets for non-ISP programming, HV Serial programming mode, HV parallel programming mode, and support for assorted daughtercards, support for legacy devices, headers for off-board use (a "sort-of arduino board"), rs232 level translators, variable supply voltage, variable aref voltage, and lots of jumpers.
But the stk500 lacks a power supply, and won't talk to a modern USB-centric computer.