It's very smooth on my iPhone 5, but it does have moments where you can notice a bit of frame drop (only if you've read this comment thread beforehand).
From a UI/UX perspective:
+ Fonts and text entry are great
+ Search speed and interface speed are fantastic
- The pull-out menu on the right (akin to a hamburger menu) feels a bit odd and it's not immediately clear as to what it does (they are layer toggles for traffic/transit routes/satellite)
- I can't figure out how to bookmark my home or work addresses (whilst being logged in) - if there is a way it is not intuitive.
You're right - it's not intuitive. To set your work and home while logged in, click the person on the upper right and then the gear then edit home or work?
Bookmarks (while logged in) require you to find a location, and then slide-up to reveal the "save star". You use the slide-up option to "Share" and "Switch to street view" as well. If it's a business, the "Call" / Website / Zaggat(?) rating is available from slide up.
From a UI/UX perspective:
+ Fonts and text entry are great + Search speed and interface speed are fantastic
- The pull-out menu on the right (akin to a hamburger menu) feels a bit odd and it's not immediately clear as to what it does (they are layer toggles for traffic/transit routes/satellite) - I can't figure out how to bookmark my home or work addresses (whilst being logged in) - if there is a way it is not intuitive.