I've had a Vario II for 2 years now, originally on an 18m contract. I was on a £35/m contract, which included WnW+ I only ever really used 10 - 20% of my call/text credit.
I just called up to ask for a MAC code, pretending I didn't know the phone was out on T-Mob yet. He asked the usual questions, I said I was paying too much for the amount I use the Vario II, and that my current phone is old hat and has been dropped too many times (which it has) - the loudspeaker and buttons don't always work.
So I let him ask me about which phones would interest me, I replied SE-X1, or the HTC Touch Pro. He advised that the Vario IV was avail, did I want to see what he could do for me on an upgrade...
So, I've upgraded. Another 18m contract on a 100minute+100text Combi 15 tarrif (which is enough for me). Still got WnW+, for £24.46/m. The phone itself will cost me £132.75 + £7 delivery, and he threw in an extra 4GB card (or a Bluetooth headset).
I thought that was pretty reasonable, given that on the site, on that tarrif, the phone should be > £300.
Hope this helps y'all !
Update 5/2/09 - Got the phone, first impression are very good! To clarify, there was a 2gb card (with a 7-day trial of Co-Pilot on) and a stylus already in the phone, a spare stylus, screen protector and slip on case in the box and T-Mobile included an additional 4gb card as part of my upgrade.