Pros:
Cliff Drive is a fantastic course with lots of fantastic features. Despite being in the middle of the city, it feels pretty secluded, with few other park features in the area and treelines blocking views of the city. At Kessler Park, you'll be throwing a lot of drives near a lot of cliffs… hopefully your disc doesn't go down a cliff.
There are now 22 holes, with plans for 2 more (see the course map). There's an official 18-hole layout, with options for several more holes if you want a longer round. The regular 18-hole layout was changed from a few years ago: old hole 12 is removed, and old holes 14 and 15 are combined as hole 14. In addition, several new pins have been installed in the last year. As a result, the course has a lot more variety and challenge while still keeping the original alignment of the best holes. The tee pads and baskets of the removed holes still exist, so there are lots of options.
In addition to the extra holes, there are extra baskets all over the place. There are approximately 34 baskets on the property, including the extra holes, practice basket, and around nine holes with two baskets each. The "official" basket is the grey one with the flag, while the others are red or blue and less decorated. You can play whichever pin you want or flip a disc to decide. I usually play the longer option unless I'm not sure the long basket actually exists, or if it's a pin I don't like (such as hole 12).
The wooded holes here are absolutely amazing. Roughly speaking, 1-9 and 18 are the wooded ones, and some of them are some of the most unique holes in the area while still being completely fair and challenging. Here are some highlights: Hole 4 is uphill with a curving fairway following a literal cliff, holes 2 and 5 play way downhill into a valley with a tunnel shot, and hole 18 is a down-and-up dogleg right. Hole 7 is an epic tunnel shot that plays through a funnel like a half-pipe. It has a long basket that would be an epic par 4, but it's overgrown so it's unplayable right now.
The open holes still have some decent variety. Since the minor course redesign, all the open holes have some hills or extreme distance to work with. Several pin placements are really precarious: hole 14's basket is under a tree whose branches block a lot of shots coming in, hole 16's long pin is on an island formed by roads, and hole 17's long pin can produce some rollaways.
The "epic value" on this course seems to be better than any other. Especially on the wooded holes, the extreme elevation makes for tons of excitement even if you're throwing off the fairway. Most of the time, there are stairs to help you navigate the hills. It is absolutely mind-blowing that holes this cool can exist anywhere and still make sense, instead of being complete gimmicks. Hole 9 has one basket placement hanging off the side of a cliff and has two completely different lines to get there.
Several of the par 4 holes are super challenging and unique. Hole 16, the island hole is one of them and is super downhill, so there are opportunities for massive shots off the tee, but with OB danger to the left and trees to the right. You can lay up for the par or go for the green in two. Hole 13 is the longest "air it out" hole, but 11 is also open and plays steadily uphill to several basket placements. Holes 9 and 18, in long pins, are fun too, but also have cool shorter placements.
Cons:
There. Are. No. Tee. Signs. There used to be, but they weren't maintained and got out of date when the new holes came in. With the abundance of tees and baskets, this is a big problem, and not even the newest map can fix the issues; come with someone who has played the course before. There are a few temporary signs on some holes, but not enough to mean anything. Even just the hole number can go a long way toward helping first-timers be confident they're at the right place. I believe there are plans for new signs in the future.
This course is in a rough part of town, so some pretty sketchy stuff goes on sometimes. Avoid this place after dark. I normally like quieter courses because it means I can play faster, but this is one course I want to have lots of other Disc Golfers at, because having more people makes place safer. Trash gets dumped at the course frequently and is difficult to clean up. In the woods, weeds aren't kept at bay very well in the summer.
An old reservoir comes into play on holes 12 and 15 and is super annoying. It's technically possible to retrieve discs out of, but it's dangerous, slow, and makes for a dumb challenge. Those two holes are easily the worst holes on the course. It has a fence around it, so there's a bit of a barrier, but it gets windy up there and discs will do crazy things.
The wooded holes become near-unplayable if there has been any rain recently, since several hills get muddy easily. There are stairs or tree roots that help, but they only go so far. And when your disc inevitably goes off the fairway, good luck. Speaking of fairways, the rough can be really nasty, especially during the summer. It's not impossible to avoid, but like all courses, anyone without multiple rounds of experience won't know what the best lines are and will find themselves searching for discs annoyingly often. Hole 2 eats up discs especially often, as can kicking or rolling down hills on 3, 7, and 10, not to mention over the fence into the reservoir itself.
Other Thoughts:
Because of the many holes and baskets, there are several variations available. You can play a "rain course" that includes 12A (between 12 and 13), 13A and 13B (between 13 and 14), and split 14 into two holes. That will give you the ability to remove 4-7 and possibly even a few others that become dangerous during and after rain. You can also split holes 11 and 18 into multiple holes or even make a 27-hole layout.
There isn't much in the way of amenities here, but I don't think that's a big deal. There's an oddly placed drinking fountain near the tee of 16 that I'm not 100% sure still works. There's no official parking lot near hole 1, but you can park on the side of the road pretty much anywhere and no one will complain.
This is one of the few courses I've played that can't improve from a redesign. That's not because the land is trash, it's because the holes here are just so good and cleaning out that long pin on 7 will make it even better. Signage is the main thing this course needs now, so once that's fixed, I might be giving this place a 4.5 rating. At that point, a few of the open holes (and maybe the litter and overall sketchiness of the park) will be the only thing keeping this course from a 5.
This course is truly a great course. It still has its drawbacks but is one of my favorites. Come during the day, preferably with someone who's been here before, and enjoy a super grueling round. It will be worth your time.