I have been using Olympus gear for over 25 years. I have never had a Winder 1 or Winder 2, but I have used the Motor Drive 2 for years, and I love it. The Winders have a rate of 2 1/2 frames per second while the Motor Drive fires at a rate of 5 frames per second. The Winders use AA batteries but the Motor Drives need a separate power source. The three options to power the Motor Drive are 1) The M. 15V Ni-Cad Control Pack, 2) The M. 18V Control Grip, or 3) a dedicated AC power source that utilizes household current.
The OM-4T(i) Body with no lens weighs 510 grams. The Motor Drive 2 weighs 360 grams and if I remember correctly the M. 15V Ni-Cad Pack is about 160 grams. The combination of my OM-4T with Motor Drive 2 and Ni-Cad Control Pack 2 has a very solid feel and I think that the combination handles very well.
All OM system units were discontinued in 2002 by Olympus, and I would guess that your chances of finding a usable Ni-Cad Control Pack are roughly 20%, although Camtech will still rebuild them using NiMh cells. The M. 18V Control Grip uses 12 AA cells and clips to the bottom of the Motor Drive or can be placed in a pocket and connected with a Relay Cord. The M. 18V Control grip has the advantage of adding a stable Pistol type grip below the camera and the use of AA batteries.
A Winder can be had for cheap but a working Motor Drive 2 and Ni-cad Control Pack 2 may cost $250 or more and you will probably need to have the Ni-Cad pack rebuilt.
Oh, the Motor Drive 2 has a LED readout that counts down the Frames remaining and has other functions as well, but there is also built in electronics. The Motor Drive 2 will allow motorized Rewind with OM-4, OM-3, OM-4T and OM3Ti bodies.