I've got a collection of Capcom arcade games on the PS2, almost all of the shmups have a similar spinning shooter mechanic as Mii Force does. Also MF even has the bubble wave weapon from R-Type!

I like Streetpass battle!

Very nice read.  I've been wondering about these games but there doesn't seem much reliable info out there.  From the sounds of it I don't get enough street passes so I'll limit myself to Monster Manor until some new idea is cooked up to make the streetpass/play coin concept work better in most of the US.

Mii Force - Probably the strongest game of the four, but it's one that I save for meets where I have 6-7 passes for the sake of balance.

Flower Town - zzzz....

Warrior's Way - Actually ended up in my usual Streetpass rotation along with Puzzle Swap and Find Mii II, though I wish I could figure out how my colleagues ended up with over 100k strong armies.

Monster Manor - I think I'm hitting the wall on this one and I'm only on the 3rd floor. I've got a good weapon now, so I hope things will get a little easier.

You guys must have different names for them over in america as there all streetpass something over here (australia)

I'm a big fan of these games- except Flower Town even though it does seem to have the most depth out of all the games. I really really like Mii force, but I beat it very fast and I'm still working on the others. I've really come to enjoy Monster Manor the most because there are a ton of weapons and items to use and there are neat ways to earn them. Lastly Warrior's Way is cool, but it's for one who gets a ton of Street Passes. I've made the least amount of progress out of all the collection, but I still like it.
The only huge complaint I have is that it now takes a while to get through Street Pass checks and it's taking away from my Animal Crossing time in a serious way. Seriously it took me about 30 minutes to get through 7 passes I got today. I don't know what people are going to do at conventions.

Personally, I like Flower Town. You can "fast forward" the talking by holding down the R button on top and get through the watering quickly that way too. What I don't like is you can't buy seeds for plants you've seen but haven't yet grown.
Monster Manor is my second favorite. Mii Force and Warrior's Way I play but don't care for. The first the controls are too hard, the other because it takes forever to build your army when you don't get many street passes. (I'm lucky to get four a month.)
What I wish is that once you purchase these games your max coins a day would increase. I don't think 10 coins a day is fair if you've shelled out money for extra games. They should increase it by ten for every game you buy.