I just (yesterday) installed an Electro Sport replacement for the later model stock unit. Fits exactly like stock, but it is a bit taller due to the finning. The main difference (besides being a MOSFET type regulator) is that the new unit has a separate ground wire, which you should run directly to battery. If you run both positive and negative outputs to battery directly, you will bypass all the connections in the wiring harness that may be a bit corroded or dirty.
Each one will cost you a tiny bit of charging current, and they add up..
All the good points being mentioned, I put one in about 5 or 6 years ago, and it did fail last weekend. However, it worked so well, when it did work, I bought another one. I got it on Amazon, for about $58.00 shipped. I think a poorly done solder joint at the stator plug may have hastened toe old units demise...
Solder all your connections, and if you haven't done it yet, make sure you take a good look at the plug between the stator and the regulator. These have been known to melt from resistance caused overheating.. Lots of riders just cut the plug out of the circuit and solder or crimp the connections. Being AC current, there is no "wrong way" to hook up the 3 white wires.. Just insulate them well with heat shrink tubing, and electrical tape. If you mount the unit in the stock location, you will have to extend the + and - wires to reach battery. Again, solder or crimp well and make sure you heatshrink the wire joints. Put eyelets on the ends of the wires, and attach to battery.