I use a low voltage 25W soldering iron, very old and made in the USSR ... The best part about it is the tip. I haven't seen other soldering irons with the same type of tip and don't know if it even has a name.
I also prefer low-wattage units for soft soldering. Anything from 15-40W is suitable for electronics work. Wattage equates to the iron's heat-holding capacity; larger irons take longer to heat up and cool down during use. Lightweight irons are actually faster overall because they reheat quickly, but larger (or more heat-dense) solder joints simply require more raw power. 50W+ irons tend to be clumsy and easily exceed semiconductor thermal damage thresholds unless awkward heatsinking tools are used; much of this can be avoided by just getting the right tool for the job.
Although most of my stuff is Metcal, I often prefer my circa-1955 10-50W "Super" and 10-25W "Mini" Scope Laboratories (Australia) soldering pencils because they allow fine temperature control by manually "pulsing" the transformer trigger. For larger (or silver-bearing) solderwork I often use a Dremel VersaTip (old electrical version) fitted with a tip-mounted LM35 and uC-automated temperature control; one of the Dremel tips can hold X-acto blades or even nickle-plated steel sewing needles which, when tinned, make superior (disposable 20/$1) fine-precision tips (they aren't copper, but still get very
hot due to their small volume-intersection). Maybe the damned Dremel was meant for woodcarving or leatherburning or whatever, but makes a good 550C silver-soldering iron. I also use a copper scrubbing pad and damp sponge (both very affordable), a jar of rosin (worth it) and bottle of liquid flux (also worth it), and kimwipes for critical cleaning tasks (****ing expensive but sometimes necessary). A little (rosin-fluxed) brass brush is awfully handy, though people might stare.
Weller is just a brand. A popular brand, largely because of its common consumer availability. There are many other brands which are better or cost less (or both). Many DIY/mod/hack methods exist to add manual or automatic temperature sensing and control to any iron. Likewise, any iron can easily be made "ESD safe". These are essential features for any real electrical soldering, but don't pay ridiculous prices for them. If you plan to do a lot
of soldering then it's worth also getting "tweezers" and "desoldering" irons, along with the usual braid, suckers, and vacuum tools. I personally never liked the old clicking relay irons, they heat too slowly and the sound bugs me.
Your special tip might just be a standard chisel/wedge which has been worn (or intentionally shaped) into a convex shape. Or it might be a variation of an SMT draw soldering "hoof" tip usually called "miniwave". A bewildering array of special tips exist but they are all variations of the basic geometries; some are designed for optimal use with particular solders, most are just marketing gimmicks. Soldering bits are very personal, just like any other craftsman tools; one man's perfect bit is another man's headache.
Yes, tips do get worn. I go through about 2-3 per week at work, sometimes more, but I use many different irons so I can alternate hot irons or use different temps or tips on the fly (I do this sort of soldering
for a living). Any given tip should last at least several months; or even years or decades for an average guy who hardly touches a soldering iron. How do you know when the tip is worn? It's pitted, cracked, blunted or misshapen; the "bad" areas will no longer accept tin. Contrary to what the makers claim there's nothing really fancy about most tips: they're made of copper, brass, bronze, or steel; plated with nickle or chromium. They can easily be machined or reshaped (or often interchanged between models/brands) as required. If you burn them out a lot then it's worth fabbing your own in batches.
Properly cleaning and tinning (and re-tinning) your tips is essential; it makes the soldering easier and extends tip life considerably. Otherwise the tip gets coated in oxides and oils: solder won't adhere, heat transfer sucks, and the tip surface corrodes. If you're just starting then it's worth reading a few guides and practicing, practicing, practicing on a few pieces of junk before actually soldering anything valuable.
The "best" temperature setting depends on many factors, foremost:
- the size, shape, mass and density of the solder joints
- exact alloy composition of existing solder and new solder
(standard 60/40(183-190C), 50/50 (185-215C), or eutectic 63/37 (183C) rosin-core soft solders are ideal for 99% of electronics, lead-free crap is also available)
- characteristics of the soldering iron
- personal preference.