Damn I hate my machine sometimes. Take two...
First thing I'm going to say is - Don't worry!
You've been off tobacco cigarettes for just over a month, now. Man, that is awesome! You need to be proud of yourself, because you've made it through the first hurdle - building a new habit that doesn't include tobacco. So, you had better be patting yourself on the back for that one. You're already healthier, and so is your family and so are your friends, physically and mentally. I'm proud of you!
Ok, you're happy with the regular batteries, filling and dripping cartos. That's great! You do not have to worry about moving on until - and if - you feel you are ready to do so. Don't worry about all the different things you hear about, as long as you're satisfied with where you are.
Nonetheless, let's look at SI and the direction SI is going.
First, 510's are also minis (cigarette lookalikes). They have a different threading, and many use 3 parts instead of two - atomizer, carto with liquid and battery. Not much different than the 808, which is what SI regular batteries are. The 808 has different threading than the 510, and combines the atomizer and carto with liquid for one piece and the battery as the second. I find the 808 more convenient, and quality wise, I find SI to above any of the others I've tried (I've had four other 808 batteries). I tried the 510's early on, back in 2008. They were ok, but I didn't stick with them, they were nothing like what is available now.
eGo batteries are 510's. They have step up batteries, eGo K, etc., all with 510 threading so cartos and accessories for the 510's fit their step ups. The new eGo Twist is a variable volt battery which is larger still, and still using 510 threading.
SI regular batteries are 808's. SI just came out with their first step up battery, the X2, also with 808 threading so you can use the accessories and cartos from your regular batteries on the X2. Now, the X2 are fixed voltage batteries, but come in three different powers, 650mAh, 900, and 1300. All are 808 threaded. Now, regular cartos will work on them, but I find the XL cartos to be slightly better. They hold just a little more liquid than the regular cartos and seem better suited for the power of the X2. I use XL cartos primarily at this time on my X2 batteries.
I will be trying one of the improved tank cartos - the clearomizer - on my X2 soon. The first run weren't so good. Anyway, this "tank" holds a lot more liquid and isn't encumbered by the filler material in cartos, and it is transparent (or clear) so you can see how much liquid you have remaining. The clearos use a wicking system, and SI continues to try and improve it with customer feedback (that's customer service). The new clearos that just came out also have a better construction, so certain acidic liquid no longer melt and crack the plastic causing leakage. These clears are best used on the X2; however, they can be used on the regular batteries, but they look pretty funny and maybe aren't giving the best flavor for the buck on the regular battery. The clearos are filled using the drip method.
Next, we have the new CE3's coming out. We've recently found that CE stands for "cartomizer edition." Remember, everyone is trying to improve on the vape, so there are going to be new innovations as we go. The CE is a clear cartomizer, again without the filler, and longer than the XL cartos, and again is for a better flavor and vape on the batteries. Another "tank carto." The CE's are great because they are filled from the top, upside down, and vertically with a syringe that creates a vacuum in the carto and prevents leaks. It also finds a way to give more flavor to the liquid and a better vape. I like the CE's better than I do the clearomizers. I'm waiting to get any more until SI's hit the website. The Phoenix by GotVapes was the first of these new CE3's to come out, and paved the way for SI to make improvements and launch their own version (SI will be coming out with a syringeless filler CE in the future). Fluxomizers fall in here too.
SI basically is coming out with things a little later than some, but remember they are 808's instead of 510's (510's having been around longer), and they have the advantage in that they can see what has failed the other companies before producing hopefully a better product themselves. Also, as with the new X2 carry case coming out, they are using their customers' feedback (us) to determine the direction they want to go with their product line, and SI has pretty much stated they plan to stay with the "starter" 808 style equipment, and don't really see coming out with variable voltage mods or such above the X2. eGo is the most recognizable brand going onward and upward. So, if you ever outgrow SI, then you can start looking at the eGo and other much more fancy mods. Keep in mind who is producing them and with what results. Expanding into homemade mods is tricky business, be sure to gather as much information as you can before making that first jump. Also, there is an 808 to 510 adapter available that will allow you to use 510 cartos and tanks on the 808 batteries, so you can experiment in that fashion as well.
Anyway, I hope I've helped a little.
Main thing is, be proud of yourself, and move at a pace that satisfies YOU, and no one else. Not me, not Imagine, not any of the other folks here or on ECF. Go at your pace.
For myself, I'm still using the regular 65mm and 78mm batteries, and I plan to keep using them as well as my X2 batteries. I love the performance of both, I like all the accessories SI offers, I like where they are and where they are going, and I'll explore new products as they are introduced. My SI 808's will be with me for a very long time.
Liquids - well, SI is first to tell you they are in the hardware business more than the liquid business. Explore to your heart's content, be sure to get samples before ordering full bottles from any vendor (and it doesn't hurt to look for coupon codes, too!).
Keep asking questions. We will be here for you.