Sierra Wireless?

[noobpadw520]

is the integrated Mobile Broadband (Sierra Wireless MC8355 – Gobi 3000 (TM)) a must have for the w520?

[Harryc]

Only if you plan to roam or travel between carriers with different protocols in the US.
Per Ken at Lenovo -

US carriers: Gobi™ 3000 Sierra MC8355 Wireless EV-DO/HSPA WWAN Minicard
- this card is dual mode supporting EVDO and HSPA for Verizon/Sprint/ATT. Only ATT needs a SIM so if you oder this card you'll get an ATT SIM.

3G for all non-US countries: Ericsson HSPA+ WWAN Minicard (F5521gw)

Specific card for China Mobile: LeadCore TD-SCDMA WWAN Minicard (LC5730D)

Specific card for China Telecom: Huawei EV-DO WWAN Minicard (EM660)

Reference - http://forums.lenovo.com/t5/T400-T500-a ... d-p/399387