I'm a relatively newer cacher (just over 4 years) who was kind of "raised on" cell phone caching (I have a GPS, but use my phone for about 95% of my caching). I have always cached with Android (I'm currentlly using a Samsung Galaxy S9+) and use three different apps based on circumstances:
- The "standard" Groundspeak app: This gets bashed a lot, but I think they've actually made a lot of improvements. The ease of viewing lists I create on the website, the ease of using the "Drafts" function, and the ability to easily use the "Message" feature usually make this my first stop. Also, the trail maps on the Groundspeak app are simply the best I've seen.
- c:geo: While they were working out some bugs in the GS app, I used this app a lot and really like it. I think the compass and distance is a little more accurate (don't ask me why), so if I'm looking for a really tough find (Like a micro in the woods), I'll use c:geo over the GS app. Additionally, I really like the ability to project a waypoint, and c:geo separates my log and my geocaching "friends" logs from everyone elses so I can quickly see my log or if any of my friends have found it. I also tend to like c:geo better for multi-stage caches...
- Geooh Live: This is the newest one. I really like the built in Wherigo player here. Additionally, you can add county and DeLorme squares to the map and this is really useful on county runs :)
While I treat each of the apps kind of like tools in a swiss army knife (Using them for specific purposes), sometimes it's also just darn handy to be running two apps at once. For example, I did a multi at Stone Mountain that was 13 stages (or so, I don't remember exactly) and had you hike up the mountain. Along the way, you passed a bunch of other caches. I did this hike "dual app", locking one app on the multi and the other to pick up the caches along the way. That way I didn't have to keep exiting out of the cache page and going back in. I use this a lot for multis or Wherigos.
I also probably have to give an "honorary" shout out to Google Maps. While I don't geocache with the app, it is responsible for getting me to about 95% of my caches . A relatively recent feature allows you to download maps for offline use, which I've recently used to great effect on some remote trips with zero cell coverate. The offline maps work seamlessly. Pretty sweet.
I also have a Garmin eTrek30. It's a decent machine, works well, and I used it a lot when I'm hiding caches (especially wooded caches), but find the whole process of transferring caches just to burdensome to do regularly. This is especially true given that all three of the apps I use above have the ability to store caches "offline", so I don't have to worry about cell service. That said, when I do transfer caches, I use either a PQ from the geocaching website, or a GPX file created from a Virtual GPS in project-GC. Other than hiding, I think I use the Garmin mostly for virtual caches that say, "Take a picture with your GPS" . I do break it out if I see a "chirp" cache (though, there's apparenlty an app for that too) or if I'm going to be somewhere especially rugged. I don't know if my GPS isn't that great or if cell phones have gotten better, but I don't find too much terribly different between the GPS and the phone. I think the biggest difference I notice is that the "compass" on the GPS is better, though when I'm phone caching, I tend to use the compass as a suggestion only and just watch the distance drop....
For cache planning, I alternate between project-GC and the Groundspeak site. I think both work well at certain things. Am I looking for "Large" caches, caches in a certain area, caches of a certain type, caches by a certain CO? Then I like the geocaching site. D/T, counties, Jasmer- then I like project-GC. I use "Lists" a lot on the geocaching site and I really like how you can easily transfer things from geocaching lists to project-GC Virtual GPS and vice versa. Additionally, I like the ability to share both of these lists with other users.
I have GSAK, and I use it from time to time, but almost never for cache planning (I really don't even understand how to use it for that?). I mostly use it to verify certain challenges and do some deep dives on some of my stats that would be hard to find otherwise (If I want to know what the first 3/4 I found in TN was, I would use GSAK). I've never created a GPX file, nor have I used GSAK to upload logs to geocaching. Whether it's not needed, or I'm just not smart enough to appreciate how much better it would be, I don't know
That's my $.02!