Is the Samsung Odyssey G5 C34G55TWW good for gaming?

Yes for fast, bright games: 165 Hz, FreeSync Premium and a 1 ms response spec make motion smooth. Dark scenes show VA smearing, so it is weaker for horror or night-time games.

Does it work well for office work and coding?

The 3440x1440 resolution fits several windows side by side, which suits coding and spreadsheets. The curve and dim panel are less ideal for color-accurate design work.

Does it have built-in speakers?

No, it has no built-in speakers, so you need headphones or external speakers connected to your PC or console.

What ports does it have?

It offers HDMI and DisplayPort inputs. There is no USB hub, so plan on connecting peripherals to your computer.

Can I mount it on a monitor arm?

Yes, it has a VESA mount pattern, which is the usual fix for its limited stand adjustment.

Is it a big step up from a 27-inch 1440p monitor?

It adds width rather than height, giving a wider field of view for games and more room for windows. Pixel density is lower than a 27-inch 1440p screen, so text is slightly less sharp.