-->ION B1 or B2
Orchard Central
Suntec City
Raffles City
Shopping online is cheaper, but there are drawbacks too, waiting for the delivery, getting the wrong size (for those english shirt makers, the sizes in Asia might not be the same as those sold in the UK, the chart on their website is quite easy to use though), for instance.
Giving the already affordable price in the retail shops here, I'd suggest get from a shop locally, unless the price difference means a lot to you.
Remember sometimes (most of the times, I'd rather say), the shirts will not fit you perfectly, and you will need alterations, and I'd suggest leave that part to the shops coz you won't be running the risk of going through a 3rd party tailor, who might spoil the shirts when doing the alteration. If that does happen, and sometimes it indeed does, then you are screwed.
I've never bought any shirt online, and I've no intension to do it in future either, in fact my plan is to tailor shirts and pants from now on, coz you get what fit
网上定一般要等多久?