Is a 3-spot laser better than a line laser?

For transferring points between walls, floors and ceilings, yes: three dots do the job faster than setting up lines. For long straight runs, alignment of cabinets or tiling, a line laser is the better tool.

How visible is the green beam?

Green is noticeably brighter than red to the eye, so it holds up in lit interior rooms. In direct sunlight or over long distances, expect to use a detector or work in shade.

What batteries does it take?

It runs on AA batteries, and a set is included in the box. Carry spares for full-day use, since AA cells drain faster than a rechargeable pack.

Does it work on a tripod?

The unit has a mounting thread for standard tripods and poles, but no tripod or bracket is included. Plan on a separate mount for ceiling and floor work.

Is it accurate enough for framing?

At 1/8 in over 30 ft, it is accurate enough for interior framing, electrical boxes and ceiling grids. For long exterior runs, check and re-shoot rather than relying on a single setup.