I find myself to be “flatwound curious” as of late. I’ve never used flatwound strings… I tried the D’addario half-rounds once, and I did NOT like them.
I’ve ordered a set of GHS Pressurewounds, as I read they’re a decent half-way string.
Any thoughts on those? Should I try them on my Aerodyne or my San Dimas?
Everything I’ve ever read or heard is that the “halfway strings are meh.
If you want to try flats, try em! I’ve got them on half my aerodynes (labellas). Love them!
Can confirm the D"addarios are, in fact, “meh”. 
I’m afraid of the commitment, LOL.
No, but seriously, as a flats user, let me ask you a couple of questions: Should I run the same gauge flats as I do rounds? Is the tension the same between equivalent gauge flats and rounds?
I guess I’m trying to figure out what kind of a change I’m looking at, if I decide to put flats on.
Gauge - yes
Tension - I couldn’t care less and pay no attention to these differences (if any).
Should you? - you’ll never know unless you try.
I use the GHS pressure wound strings on my G&L L-2000 because the pickups are very hot and I like the tone but only in connection with that bass. They are all but flat to the fingers. In my experience Rotosound flats are great, they are quite “alive” compared to GHS flats or LaBella. If you want the classic flats tone for rock go for Rotosound. If you want to save some money get Fender flats, they are good. If you can spend the money and want the thumpy vintage sound go for LaBella. Just don’t get short scale Rotosounds.
I can’t claim I am a flats lover, @JustTim ! But, John is right - you will need to try them! No amount of reading what others say will be a substitute for you trying for yourself. Or tell you whether you like them…
On which bass? Might be a tough choice - try them on several if you can. For that, remember not to cut them before you have tried them on different basses (unless they have the same scale lengths and headstock layout 
)
It depends.
Flatwounds in general have a higher tension. LaBella’s Deep Talking Flats have a higher tension. One reason they make Lower Tension Flats as an alternative. But not all flats are high tension, Thomastik-Infeld Jazz flats are among the most flexible strings on the market of any type.
If you’re not going for the old school vibe I would really recommend a modern flat with a round core (as opposed to a vintage flat with a hex core). They will be lower tension and produce a brighter sound, more balanced. LaBella LTFs and DA Chrome flats are good options. TI is the best, but you may balk at the cost.
If you’re really not ready for flats, go tapes. You will get a more mellow tone. Everything I hear on half rounds is bad. Tape wound is a better “I can’t commit” option.
Or you can go DR Pure Blues to get a warmer sound in rounds.
It depends
Is what I did! Amazingly and astonishingly interesting strings!!
Meh…. I love tapewounds (labella and D’Addario, both very different) but they are a more specialized tone and not good for “everything”. Flats have more versatility IMO.
I don’t disagree, they aren’t as versatile just think they are a better option than half rounds.
There’s a reason why for all the dozens of string options, there’s one half round being made
Commit! 
I put the Thomastiks on the P bass last week, couldn’t put it down for days!
They are a good string.
I love love love TI’s on my 54P. It just makes that bass’s notes bloom and sound almost bell-like. Beautiful tone and really easy to play. The rounds by TI are as good if not better. Thomastik makes great, albeit expensive strings.
I don’t have much to say, my experience with flats is rather limited. I really enjoy the labella deep talking bass I put on my second-hand pj. Totally different from the sound of rounds I was used to, great opportunity to contrast and compare tones.
And the eb cobalt half-flats are nowhere near as half “flatwounds” in tone, imho. Feeling maybe, but only that.
Commit 
Gah. I first read this as “tapeworms”. 
If you don’t like flats and try them it would be cheap just a set. The problem will come when you like them, then it will cost you a lot to change, lol.
Tapewound/ Nylon wound are a great alternative. TI Jazz flat is on another league altogether.
Yeah. Flats aren’t my bag but if I wanted to use them I would go all in with T-I or LaBella and just skip any hybrids.
This^^^
TI Jazz flats are superb. Yes, they do cost, but they last virtually forever and their playability makes ‘em worth every penny.
Hi tim. I run the Bella deep talking flats on all three of my guitars. Will never go back to round wound strings again.
Flat round strings have to be measured and installed precisely. If you’re not familiar with how to do this, give the techs at la Bella a call and talk to them first. If you get them too long they will break. You only wrap the silk portion of the string around your tuner, not the flat wound part…
Take a couple of minutes and make a call, figure out how to do this before you order. You won’t regret it.
They have a sizing guide on their website that is very straightforward too. @JustTim - IF you go with LaBella and IF your bass your putting them in is string-through (not the Aerodyne) then it’s a different string due to what @ronnielyons is mentioning but on the ball side. ( Note at least for future reference).