If you aren't bothered about receiving your pre-release order by the release date, or even having it despatched by the release date, then based on my experience, you could do no better than shop at WH Smith On-Line. In fact there's a fair chance you won't receive your order at all.
I ordered 3 pre-release DVD boxsets at the end of October. The first of these was released on 3rd November. It didn't even get despatched until the 10th, and only arrived this morning. The second boxset was released on the 10th, got despatched on the 11th (after several complaints by phone), and hasn't arrived at all. The 3rd boxset was released today, and once again has failed to even despatch. I spoke to Customer Services this morning and they told me that it is because their supplier hasn't received stock yet. Funny that, because it's been showing on my account as being in the despatch process since last Wednesday. Also odd that the local WH Smith store seem to have it, as do Play, Zavvi, Amazon, Sendit etc. As the same distribution network supply all suppliers, I can only assume that WHS Customer Services are full of BS.
Still, it makes a change from the excuses they gave about the late arrival/non arrival of the first two orders - Royal Mail. I'm sure we all agree that Royal Mail sometimes get it wrong, but it annoys met when on-line suppliers use them as an excuse for their own inepitude. As for the WHS on-line contact form - it states that they will endeavour to reply within 24-48 hours. Well, I've e-mailed 8 times in the past 2 weeks and had not one response. I was so angry at the end of last week that I sent another email, and copied it 50 times to them. Interestingly, I received a response within the hour, although it was typically unhelpful and offered the same lame old excuses. I normally use Play.com and Amazon, but thought I'd give WHS a try because this site had a 10% off voucher posted. What a big mistake, cos it's cost me far more in phone calls to their hopeless customer services than I actually saved. I just can't seem to make them understand that when a customer places a pre-release order, they would actually like to receive it by the release date, not a week or so later, or maybe not even at all. Play & Amazon seem to manage delivery on or before release date the majority of the time, so I can only assume that they are a great deal more competent than WH Smith. So, based on my own experiences, if, like me you are purchasing a time critical item such as a birthday present (especially if it is a pre-release), then avoid WH Smith on-line like the plague. A 10% discount voucher sounds good, but it simply isn't worth all the hassle.