I am not sure whether I'd need to upgrade to a Z Ultra 2, though I probably would anyway as mine is the HSPA model without LTE.
The only time my XZU lags is when some badly behaved website causes the browser to eat all the RAM, or a badly behaved app, and these would probably kill any device.
The XZU1 is right at the limit of pocketability for me, which makes it perfect.When I had a note 2 I loved the pen but felt i could handle bigger, but a tablet would be too much. Once you've gone two handed you want the biggest?
I had the use of an LG G Pad 8.3 for a week do I know I'd definitely find the Z3 compact too big to carry all time, though I wouldn't mind wearing an SBH80 all the time, something I've considered as an upgrade path.
With prices of the XZU at rock bottom, and no concrete evidence of an upgrade, I am tempted to buy a spare! Or rather, get the LTE variant and put this aside as a spare.
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Android phones: Xperia Z Ultra, Galaxy Note 2 N7105, HTC Doubleshot, HTC Vision.
Previous phones: Nokia E71, E65, 6310i, 2110.
Previous PDAs: Sharp Zaurus C3100, Zaurus 6000L, Zaurus C860, Palm T3, Sony Clie N770, Handspring Visor.
Mobile operator: Three (latest), Vodafone, Three, O2, Orange (oldest).
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