Just got my SP4 Pro yesterday. i5, 128GB with 4GB RAM, just like my SP3Pro.
SP4 vs. SP3.
The likes:
Speed. Quicker doing everything. Not by leaps and bounds but noticeable.
Size/fit/feel/weight. All better.
Pen. The pen is excellent. Writing with it feels much more natural.
Touch Screen Response. Better. I have fat fingers, when browsing sites, etc, it's much more responsive to my touch rather than having to tap something 2 or 3 times.
Windows 10. This device was built for it. Little quirks that don't work right on the SP3 (wake without password for one) works perfectly here. Hello is nice as well. But a little flaky depending on back light, environment, etc.
Dislikes:
Does not fit in the old style dock like the SP3 does. I have 5 of these docks at work, the fit sucks. I have the new dock on order, but it's supposed to fit. It's a crap fit.
Screen texture. Just as with the SP3. Too glossy, too much glare. Looking for a matte protector like I have on the SP3. The ones I have will cover up the Hello camera and I'm not trimming them.
Screen pixels. I use a dock and 23" monitor. Resolution changes perfectly now, but scaling is still off. If I take it off the dock, any text, etc., looks kinda grainy. If I log off while the device is off the dock, log back on, it's perfect.
On my SP3, I take it off the dock, icons are small, but text, etc, all look fine.
50/50 list.
Pen mount. I can go either way. Yes, it's sexier than the loop. But when you pull it out of your bag/put it back in, It's already popped off twice. With the old style docks...you just stick it to the side. With the new style dock, this won't be an issue.
I have the new dock and new keyboard w/ fingerprint on order/backorder from my supplier. No comment on those yet.
I am an IT Manager who uses the device for normal office functions day to day.
I'm not a gamer, hard core video editor, graphics designer, etc.
The SP3Pro was my only machine to use since last year, this device will be the same.
I think in the last year at home, I sat at the family desktop 4 to 5 times, to "fix" something...
If it were my personal money to spend, I honestly would say for my work, the SP3 Pro is just fine.
But because I have a budget for new technology and I can very, very easily hand down my SP3 Pro to a coworker, etc., I like having the ability to try and use new things.