This is not to really detail the difference, or provide any comprehensive explanation.  This article is to show what I've learned and what I've tripped over in order to do so, and to provide information.  I strongly suggest some sites like http://www.howtobrew.com/ for John Palmer's site (reference Section 1, Chapter 10) and many other sites which I will eventually understand more about.

Well, it turns out, after further review of the recipe, that what I had done for beers 3-6 was use a lager yeast, rather than the rest of my earlier and later beers (so far) which have used ale yeasts.  The's the old saying about the difference between the yeast is a top ferment vs a bottom ferment, but there are many exceptions to it and doesn't really clarify the topic since in some ways, yeast is yeast. They all eat sugars and produce alcohol and carbon dioxide.

The main difference that I now see, is that lager yeasts like a lower temperature than ale yeasts (45-55 vs 60-70 degrees F)and will (ideally) produce a cleaner, crisper tasting beer, regardless of the hops used.  The lager style of beer is also more of a light golden color, rather than ales which tend to be darker, ranging from a light brown down to a dark black.  Ales will get a lot of flavor from the sugars and the yeasts, while lagers generally don't get quite as much yeast flavor unless it's either specificially worked that way, or accidental.  My yeast flavors in 3-6 were accidental and the taste differences are probably due to temperature fluctuation.  My temperatures were really in the ale range, not the lager range and that's why I noticed odd flavors that I think reminded me of bubblegum or banana. 

There's a lot of history which is pretty interesting, about how beers were stored in cooler caves because of the too high temperatures outside, giving the name lager from the German word to store.  Makes me wonder if the colder temperature made everything settle so that the active yeast were at the bottom, rather than floating around, giving that whole top vs bottom difference.

There seems to be specific techniques when creating a lager, involving first the initial fermentation at a low temperature, where the temperature depends on the yeast strain.  For example, the Fermentis Saflager S-23 and W-34/70 recommends 9C-15C, ideally 12C.  This cooler temperature prevents the fruity esters from developing, and of course because I didn't do that, I did wind up getting these esters.  There is then the possibility of a short, slightly warmer temperature rest, called a diactyl rest.  Diactyls are produced from the yeasts during the fermentation and may give a buttery flavor to beer.  (See here for a description).  The yeast will eventually absorb this but higher temperatures allows the yeast to do this quicker.  Which is probably why I didn't taste or smell any of it. 
After the possible, but maybe not necessary diactyl rest, there's the lagering phase, where the beer gets to rest from one to two months at a low temperature.  John Palmer recommends that a 10 degree F difference is involved and that 45F would take a month while 35 would take 2 months.  This means that I can't really depend on my ambient temperature but need a fridge, or otherwise insulated container.