Script component to add to GameObjects to easily show debug text above within Scene view

DebugText.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

/// <summary>DebugText class
/// AUTHOR: Beard or Die  (more or less)
/// BASED ON AND THANKS TO: Video and code by Unity3d.college: https://www.youtube.com/watch?v=uFFexymk3FY
/// DATE: 2018-01-11
/// COPYRIGHT: None; even remove this text if you want.
/// PURPOSE:
/// Adds a customizable text viewable within the Scene tab, even when not in Play mode
/// You can choose between the built-in data types to be shown, or customize the debug data. 
///
/// INSTRUCTIONS:
/// If using Override mode to set custom debug text, in order to prevent
/// "OverrideText method not yet called. See instructions." being shown, 
/// in any another script attached to the same GameObject, use the following code:
///
/// private void OnGUI()
/// {
/// 	if(gameObject.GetComponent<DebugText>()!=null) gameObject.GetComponent<DebugText>().OverrideText("myVar1: " + myVar1 + "\n" + "myVar2: " + myVar2);
/// }
/// </summary>

public class DebugText : MonoBehaviour {
	[HideInInspector] public enum DebugDataTypes {TransformPosition, GameObjectName, GameObjectToString, Override}	
	[Tooltip("Choose type of data to show")] public DebugDataTypes useData = DebugDataTypes.TransformPosition;
	[Tooltip("Adjust position of debug text relative to object")] public Vector3 heightOffset = Vector3.up;
	public Color color = Color.green;

	private string overrideText = "OverrideText method not yet called. See instructions.";


	public void OverrideText(string newText)
	{
		overrideText = newText;
	}



	public GUIStyle style;

	#if UNITY_EDITOR
	private void OnGUI()
	{
		DrawText();
	}
	#endif
	
	#if UNITY_EDITOR
	private void DrawText()
	{
		string text = " ";
		style.normal.textColor = color;
		style.alignment = TextAnchor.MiddleCenter;
		style.fixedWidth = 300f;
		switch (useData){
		case DebugDataTypes.GameObjectName:
			text = gameObject.name;
			break;
		case DebugDataTypes.TransformPosition:
			text = gameObject.transform.position.ToString();
			break;
		case DebugDataTypes.GameObjectToString:
			text = gameObject.ToString();
			break;
		case DebugDataTypes.Override:
			if(overrideText!=null)
			{
				text = overrideText;
			} else 
			{
				text = "OverrideText not yet called. See instructions."; // to prevent this, see instructions
			}
			break;
		default:
			text = gameObject.ToString();
			break;
		}
		
		
		UnityEditor.Handles.Label(gameObject.transform.position + heightOffset, text, style);
		
	}
	#endif
	
	#if UNITY_EDITOR
	[ExecuteInEditMode]
	private void OnDrawGizmos()
	{
		DrawText();
	}
	#endif
}

Result Preview:

Updated 2018-01-13 with the help of Darkfafi and B.A.R.A.N.U.S.: now visible in Game view also, and does not cause build problems.