Whether it has all of the bells and whistles of the original is irrelevant if those features sit paid for but unused. The situation is no different than discovering that the person who insists that they "need" Photoshop is just using it to draw a few geometric shapes and remove red-eye from photos what they really need is a graphics editing tool that can replace those specific functions. The trick for deciding whether a replacement piece of software, whether open or closed, is a good choice for you is to tease out exactly what your needs are.
But I would argue that the reason for your disappointment has nothing to do with the licensing of the product-drop-in replacements for complex programs with long-time users who have specific needs and expectations for their software are hard. Let's start by being honest and upfront about something: If you're looking for a drop-in replacement for your existing CAD program that will provide identical functionality and workflow without making any changes to your processes, you're going to be disappointed. So how do the open source alternatives to AutoCAD stack up? The answer depends on how you plan to use them.
Even hotkeys require you to hit a letter or two plus the Enter or Spacebar key. There are not many things you can do in AutoCAD with only one keystroke. If you like it but only at times, this key will help. It seems to me that you probably either love Dynamic Input (which puts the Command Line and Status Bar information near your pointer in the work area) or you hate it. F12 - Toggles Dynamic Input on and off.This key makes it easy to turn it on and off as needed. Some designers use Object Snap Tracking all the time and never turn it off. F11 - Toggles Object Snap Tracking on and off.In the same way that F7 and F9 are “sibling” function keys, F8 and F10 are siblings and are often used in tandem. Note that when you use this key to turn Polar Tracking on, Ortho is automatically turned off. Very useful when working with designs having more than one geometric orientation, as when part of the design is rotated 45 degrees in relation to another part. F10 - Toggles Polar Tracking on and off.F9 - Toggles Grid Snap (snap to grid) on and off.I use this key in combination with the F9 key to organize text objects on a regular grid–see Tip 1011. Now use the F5 key to toggle between the three sides of the object you are drawing: top, right, and left. Then under Snap type, choose Isometric Snap. To get into the Isometric drawing mode, hover over the Snap Mode button at the bottom left of the screen, right-click, and choose Settings.
For drawing “fake-3D” isometric drawings.
F2 - Opens the AutoCAD text window, which shows an extended view of the Command Line entries.
I actually think that is probably the best idea, as long as you keep the key stashed away so you can put it back on if needed. Here’s a radical solution: one CADster friend of mine actually pops the F1 key out of his keyboard using a screwdriver so that it can’t accidentally trigger the Help window.
It’s right next to the heavily-used Escape key, often gets bumped by mistake, and is likely to frustrate the CAD user who is constantly needing to hit Escape to get free of a “sticky” command such as the Line tool. This key can be more trouble than it’s worth. F1 - Opens the AutoCAD Help window, v-e-r-y s-l-o-w-l-y.Diagram of the Function keys and their functions