I'm looking at the Milwaukee 5616 router. It appears, at least in the videos and literature, to have a more precise and easier to make adjustment than the Porter Cable 690. Twisting the motor in the base of the 690 and getting down to a 1/64th"is a hit and miss type thing. I'll be looking at the 5616 in the store to see if it actually is all it advertises to be.
The PC 690 was my very first router, I can not say that I ever had any problems making precise depth adjustments. Iin fact, I found it quite straightforward in that regard -- my experience was quite different in that regard. You may have some issues if the base clamping adjustment is left extremely loose as you will then be fighting gravity, but if you adjust it to allow a light friction fit then the adjustment will stay put while you set it and lock down the base. Judging from recent photos online I do not see any obvious changes made to the base or the adjustment over the intervening years, so the new models should work just the same as the older units.
You can also use the depth gauge ring on the router base to make fine adjustments by initially zeroing the ring out (after adjusting the bit to be flush at zero depth using a piece of wood or aluminum as a feeler gauge) with the vertical score line in the motor base, then rotate the motor in the base by the desired measurement on the depth gauge ring (if things have not changed then it should be calibrated in 1/64" units IIRC). I frequently used either the depth gauge ring or a simple ruler held against the router base/table and then read off the depth directly against the bit's cutting edge.
For many years it was my only router and was well used both freehand and in a router table, and never any issues setting it up for precise cuts. I also have several modern PC 890s (including one permanently installed in my router table), but they have a totally different base design. My only real complaint was that my PC 690 did not support speed control, though some of the newer models may add that feature (???, the modern 890s do have speed control).
Fortnately there are a number of very nice and affordable entry level routers these days from the major manufacturers (just stay away from the really cheap routers like the Ryobi and Craftsman models as they have many compromises).
However, you may wish to start out with a 2-1/4HP router (such as the PC 890 dual base kit)
with built-in speed control and a kit with both the fixed and plunge bases. These make for a much more versatile router and are equally at home for use as a freehand router and in a router table. The speed control allows you to slow things down for more control when freehanding critical or heat sensitive work as well as for working with larger bits in your router table. They cost a little more up front, but they greatly expand what you will be able to do with your first router. The only advantage that the smaller ~1.5HP routers offer is slightly less weight than their 2-1/4HP big brothers. However, I do not recommend the full size 3-1/4HP routers as a first router as they are both very heavy and powerful and a bit much for most (esspecially beginners) to use freehand and are often most at home mounted in a router table for those large jobs (like cabinetmaking bits).
Whatever you decide upon, I wish you the best in your adventure!