In terms of web browsing, 5530 XM totally rules in displaying and navigating websites due to its relatively huge and high resolution touchscreen, 5730 XM's 2.4' 320x240pixels non-touchscreen(which means u have to tab or use the navigation keys) is no match for 5530 XM's 2.9' 640x360 pixels touchscreen.

However, if you're not familiar with touchscreen, typing/texting could be very clumsy, if you really text a lot (I mean really alot), or perhaps u like N-Gage, then you might want to consider 5730 XM.

I'm telling this as a 5800 XM and N73 ME user, not so familiar with mobile QWERTY but I'm sure it's way better than virtual QWERTY.

Just my 2 cents.

A little opinion of mine:

1. Value for money:
- 5800 XM is definitely value for money, good feature-price ratio.
- E63 is quite good.
- E71 is relatively expensive due to its popularity.

2. Office apps:
- E71 is quite snappy and has full QWERTY keypad.
- E63 is close to E71 minus the exclusive-ness.
- 5800 XM is not meant for office, virtual QWERTY is not for prolonged typing and it doesn't even has pre-installed office apps.

3. Performance:
- E71 is snappy.
- E63 is similiar to E71.
- 5800 XM is relatively slower.

4. Cameras:
- 5800 XM although it's not very good but compared to E71, it should be better and has better LED light.
- E72, 3.2MP with AF.
- E63, 2MP without AF, as it's a budget phone.

Overall, if your focus is on office apps, E71 should do better, 5800XM is a multimedia phone that focuses on music, video and web surfing while E-series is for business which suits your requirements. If you can afford E71, I think you shouldn't be concerned about E63, it's a lower end of E71, E71 has everything E63 has + better camera, GPS and HSDPA, unless you want a 3.5mm earphone jack and don't need those extra.

There is no way that K700, such an old model which:
is a 2G phone with 1.7 inch 65k colour 176x220 pixel display, 0.3MP camera without AF nor lens cover, 41MB memory & no memory card support,

can sell at a higher price compared to K770 which:
is a 3G phone with 1.9 inch 256k colour 240x320 pixel display, 3.2MP AF camera with lens cover, support M2 memory card.

It's either:
- the seller is trying to con you,
or
- the seller is selling the K700 as an antique.