I use both a flat CI and the one with the ribs, both by Lodge. It looks like you've resurrected your old CI. Since they never wear out, that is sensible.
You need to pay very close attention to the temperature of the skillet if you want to get good results. There are two ways to do this.
If you have a point-n-shoot IR thermometer, you can use it to read the surface temp of the skillet. You want it REALLY hot. Some suggest a temperature as high as 500 degrees.
If you don't have an IR thermometer another, perhaps even better way, to heat the skillet for searing is to put it in the oven, with the temp set to between 450 and 500. Leave it there for at least twenty minutes, while your steak cooks outside. This does two things. First, it gives you a way of getting the correct temperature without owning an IR thermometer. More important, however, is that it gets the skillet uniformly hot. CI is notorious for extremely uneven heating. With my IR thermometer I regularly see 100-150 degree differences across the surface of the pan.
I use the ridged pan mostly for panninis. but also for steaks which I cook from scratch on the CI skillet rather than simply finishing them there. The grill marks are nice, although I don't think they make it taste any better. More important is the ability to get the fat and moisture away from the meat so you neither stew nor fry the meet.
Finally, if you have lots of money, or you have a son who likes to treat his dad at Christmas (which is how I got mine) you can get a Searzall torch. Others have suggested a weed torch, or just a regular butane torch, but both can impart a flavor to the meat. The Searzall heats a mesh which then re-radiates the heat to the meat. For me, it was a total game changer. I can now get a better sear on a steak than I ever got on the grill on on a CI skillet. I use it on lots of other things, like getting a nice brown on mac 'n cheese. The other big advantage is that you have total control over how much browning you get because you can instantaneously see the meat (or mac) turning brown.
[edit] I just saw the post about CI searing possibly over-cooking the meat. That is indeed a real possibility and is another reason I have become such a fan of the torch: it get the meat extremely hot at the surface, but doesn't have enough total energy to heat up the inside of the steak very much. You still have some residual cooking from the hotter exterior (from the cooking, not the searing) continuing to penetrate the meat for 10-15 minutes after you pull it from the grill, but that is nothing compared to what the scorching on the CI pan will do. So, when you sear on the pan or griddle, pull the steak at least one step below your desired doneness, e.g., pull it at medium-rare if you really want medium.