The 5205-s703 is a really nice machine. You're definitely going to give up processing speed compared to a 5660 (also the Toshi is running on a 400 mhz fsb vs the Sager's 533 fsb, plus the fact that you can easily upgrade the processor on the 5660). The video chipset performance will probably be very close between the two, although the Sager's faster processor and bus will help that along. The s703 has the 15" UXGA Toshiba Personal Home Theater screen, which is beautiful, very bright and sharp. I've compared it to the Dell Ultrasharp and preferred the Toshi. I haven't gotten to see the new 5660 UXGA screen in person yet so I'd love to know how they compare, everyone's had great things to say about the new Sager screen though.
A couple of other things on the s703: the harman cardon speakers with built in subwoofer, definitely the best sounding laptop speakers I've ever heard. They're loud and dont distort when they're cranked up. The DVD writer is nice, but you can order the 5660 with one. Built in 802.11 wireless, you can order that on the 5660 too. The 5660 has more legacy ports. The s703 has no serial, parallel, or PS/2 ports, and no floppy drive. Then there's the main thing.. battery life. It lasts almost 3 hours on the primary battery and can hold a second battery in its option bay, which should push the battery life to 4.5 to 5 hours. The 5660 lasts about 2.5 to 3 hours on dual batteries (from other reports on this board).
In the end it comes down to that decision.. battery life vs performance. Price is a consideration too, you're going to end up paying at least about $2000 for the s703. You can get a nice 5660 2.4 ghz, 512 ram, 5400 rpm drive, UXGA, etc, from PCTORQUE for under $1700.
One last thing.. be VERY wary of the 'brand new sealed in the box never opened not refurbished' laptop deals with prices that are too good to be true that seem to be all over Ebay these days. Most, if not all, of them are straight up scams or are peddling stolen merchandise. Two days ago I saw a 5205-s703 go for $1300 Buy It Now. ($1300!!) I'm planning on getting a Sager, but that laptop for $1300 is a crazy deal. The seller has over 2000 positive feedbacks with only one negative.. not too bad I'm thinking. So I emailed the seller to see if they have any more at that price. They emailed me back saying they have more that they can sell me for about $1470 (1300 Euro). They're located in Europe and want me to send them the funds through westernunion.com as soon as possible. There's red flag number one. I emailed them back and said I would only buy it if we went through escrow.com so I could be protected. Of course they dont want to go through escrow, even if I'm paying all fees. Then a similar situation happened again to me today.. Last night I was browsing newly listed laptops on Ebay and I came across an auction for brand new sealed in the box Dell Inspiron 8200's, 1.9 ghz, 256 mb, 30 gb, GForce4 440 32 mb, Ultrasharp UXGA, etc, for $980 Buy It Now. They had about 20 of them. The seller has all positive feedback. I'm really waiting for the M10 to come out on the Sagers, so I decide that I'll buy this Inspiron for now, wait 6 months or however long it is until the M10 is out, then resell the Inspiron and buy the Sager (that exact Inpiron goes for about $1700 on Dell's site right now). Perfect plan. I placed my bid (used Buy It Now) and got a email shortly thereafter from the seller with payment instructions. I find out in the email that the seller is located in Lithuania and they want me to send the payment via Western Union as soon as possible. No way I'm sending $1000 to another country through Western Union with no protection, I dont care how good the seller's feedback is. Well, low and behold, this afternoon I get an email from Ebay saying that they ended the auction and cancelled all bids because they suspect the sellers account had been comprimised. They email was very clear in saying that I should not send any payments and even had some instructions on what to do if I'd already sent a payment. The way Ebay put it, it sounds like crooks are putting up auctions by hijacking honest Ebayer's id's, which makes them look like they have great feedback. Then they collect your money (usually in another country), and you get squat. My advice for buying a laptop off of Ebay (or any other high priced item).. be careful, find out anything you can about the seller, and use escrow to really protect yourself.