ANY of the methods presented within this thread are certainly applicable to your project. I believe that all would work, and work quite well. There are perhaps even a few that have not been mentioned. Some methods will undoubtedly provide a mechanical advantage by design but in application add very little to this particular build and therefore do not warrant the additional expense for new equipment.
I humbly suggest that you stay focused on the two methods originally questioned. Either will provide you with the needed strength and durability needed for a successful project. You have gained the experience of using both and I do believe you are both confident and comfortable with the application of either.
The grass isn't always greener, but sometimes it is.. for now, however. stay in your own yard
It is not hard to find advocates for any of the methods mentioned. When it comes to joinery, that ole cat gets skinned 6 ways from Sunday and then some. Of the two methods you've queried about, I'm not a big fan of biscuits as you know. I do however use em when its makes sense. In fact, I used them on the seat for my rocker build. Just because that was the suggested method for joining the boards. The advantage to biscuits has been mentioned repeatedly. Ease of application and you get a bit of wiggle room during assembly. It is also generally agreed that biscuits are stronger than dowels. "Generally", not unanimously. The down side to biscuits is that they have been known to swell after application and create small rises on the surface of the wood above. This often can be found on softer woods and in thinner stock. I've had this happen a few times, but never to the extent that it presented a real problem. A little extra sanding and all was well. Dowels on the other hand in my opinion provide a stronger joint. I realize I may be completely wrong about that and most of the data you'll find won't support my thinking. But it works for me. Application of dowels can be extremely difficult without quality tooling. Without quality tooling, its extremely difficult to get proper alignment of the work pieces. Though not impossible!!! You just got to be real good, real lucky or real experienced (or any combination of the three) to do dowels freehand or even with a modest doweling jig. You have a quality jig, and have become proficient in its use. Any errors you've encountered have been recognized and adjustments made to your technique.
For this particular application I'd personally say that the biscuits have an advantage over the dowels in so much as that during glue up, you can make some adjustments
to align your surfaces.
Regardless of which you choose, its not uncommon to have some variation between surfaces especially when your looking at things from the .000 of an inch perspective. nothing is 100%, 100% of the time..