Some of it depends on how you'll be using it. If you intend to use it with other cameras.
Originally Posted by Max Power
1) A wide range of F/stops. You can fool a little with the film speed to get around this but it'll slow you down. Easier to set F/11 when you want F/11 then to change the film speed and tell the flash you're using F/8.
2) moveable head.
3) Fast enough recycle time for your needs. This will depend on what you're doing. A wedding guy is going to need a lot of flashes fairly quickly. Other less. If you need a lot of flashes then it might help if you got a flash with easy quick battery changes.
4) A good autosensor.
It's nice if it's still reasonably supported but if it's cheap enough like my Agfas then it doesn't really matter.
In todays market I've bought a pair of Metz 45 for very little. The CL-3 was about $50US. I think I paid $80 Canadian for the CT-3. They have brackets. I think you're using a TLR so the bracket might be a plus for you. They take Metz 300 and 3000 modules so you can even use them with modern cameras by just adding the right cable and module. Or you can use just the basic sync cable with your TLR. I'd avoid the CT-5 because it needs a no longer available module. I'd also avoid the CT/CL -1. These don't provide TTL etc but they don't cost much less on the used market.