I’ve used dypys divers, slide divers, jet divers and snap weights. They all have pros and cons.
Dypsys are directional allowing you to spread out your lines. If you stop, dypsys will sink. They pull hard as others have said above so you need a stiff trolling rod. Depending on the model and how you set the tension, not all will disengage on a small walleye. I guess they now make a superline dypsy but I have not tried it.
Jet divers are inexpensive but they are not directional (they don’t spread out). When you stop – they float to the surface. They don’t pull as hard as dypsys. You have to buy them at 20, 30 and 40 feet.
The slide diver is directional and you can very your lead length without retying. It can detect smaller fish better than dypsys. The thin braids have a tendency to slip so some guys splice in heavier mono line to attach it or use mono or they put on a stop bead and a swivel on their braid. I also heard surgical tubing works with braid too. You also have to cut the line to remove it.
Snap weights are another cheap way to go. You attach it right on your line – 50 feet up from your crankbait. It’s not directional. It’s very speed sensitive. At a 60 degree angle (trolling speed + snap weight) you multiply by 2 to achieve desired depth (50 feet from snap weight to rod tip will get you 25 feet of depth) plus you need to add your 50′ depth curve of your crank bait. At a 40 degree angle – multiply by 1.4. You can not do S turns with snap weights and need to troll straight lines otherwise they will bottom out.
You can catch fish with all the diving tools above. However, leadcore is the most versatile, consistent and easiest way to control your depth of your lure. It’s not directional though. However, with the use of planer boards you can get it away from your boat. Some guys attach it right to the board but you need to be careful because you can damage the lead core line. This is where segmented lead core comes in. You have a leader then splice in your lead core (3-5 colors) then tie that onto braid or mono which goes back to your reel. You then attach the planerboard right after the lead core on the braid or mono line. Only drawback is that you are pretty much locked into that lead core depth (3, 4 or 5 colors). You can gain some depth by attaching the planer board further away from the lead core line but it’s hard to be consistent.