I love my packmate twist lock ones - they are jumbo sized and gusseted so they stand up. Much more sensible for packing things in tbh! The twist lock thing means that you can twist it closed while vacuum still attached and so no chance of air getting back in. A bit pricey though... But can fit heaps in each. Pretty sure I had a 13tog king duvet in one if mine last year, with 2 pillows.
However, 2 weeks ago I bought a load of ikea large ones 100cm x 60cm for less than £3 for a 2pack (reduced sale price). None have reinflated yet but can't give long term view. Certainly value for money if they hold up.