Questions to ask as I shop for a tonearm?

@toschsii,
You're being very smart to ask those questions. It's a complicated and often frustrating subject for some. You are lucky that there are many helpful experts here. I would suggest paying close attention to comments from
@almarg @raulariegas @nandric, @chakster, @lewm, @dgarretson, @atmashpere who all make regular contributions on this topic.

I'll mention one tonearm consideration that you should familiarize yourself with:
The relationship between tonearm and cartridge. Resonance is a big concern with a known and agreed upon range of what works best. Too low a resonant frequency or too high will cause huge problems in sound quality and tracking ability. vinylengine sit has a resonance calculator that is a well-known tool that lets you consider the compatibility of any given cartridge and tonearm. It's not perfect, but it is a perfect place to start to understand the concepts and get lead you in the right direction. Pair a cartridge and tonearm that lead you to a resonance in the green range. One quirk is that Japanese companies present different specs than most Euro or US ones, so if considering a Japanese cart, by sure to convert the specs so you get "apples to apples". (This will make more sense after a bit of reading). 

Though not about tonearms, another important aspect to understand is the relationship between cartridge output and phono stage gain. Carts put out very small signals. Phono stages, or phono sections of preamps that have them built-in, add a certain amount of additional gain(often adjustable). To get reasonable performance you need to have enough gain but not too much. Some very low output carts needs an extra boost(step up transformer). Moving magnet carts need less gain, moving coils more. Many phono stages are made to focus on one or the other, some both. Making sure your phono stage has appropriate gain settings and loading options for the cartridge is a critical step to enjoying vinyl.

I'm sure plenty will chime in with good advice Cheers,
Spencer

@williewonka Thanks for that post. I just bought an Audiomods V, which is at Sota to be mounted on the new Series Six Nova they are building for me now. My hunt (discussed in another thread) came down to the Audiomods or the new Jelco 850, 950s.  I am one who adjusts VTA for every LP played. An aftermarket VTA adjustment base made specifically for the Jelcos ~$200, kept it under consideration. The Audiomods has their own built-in micrometer as an option. A great deal on a pre-owned Audiomods w/micrometer from a fellow 'Goner made it an easy decision for me.

The Trans-Fi Terminator was something else I considered. Having spent plenty of time with a friends' TFT, I just couldn't get comfortable with its tweakiness and apparent fragility. The delicate exposed wiring scared me a bit. Had more than one visit where "TFT down again, let's listen to digital". Lately he's worked through his issues and is very pleased. While the micrometer VTA has some appeal, the digital display reminded of a $5 tool from Harbor Freight. The large dial was also more awkward adjusting than you'd expect and inferior to the dials on other VTA adjusters like those on VPIs or the terrific one on the Technics EPA series that I used to own.   

Someone correct me if I'm wrong, but I thought I read that the Michell arm mentioned is made for them by Jelco, as are a number of other companies' arms. If so, that would make me think that a Jelco branded arm might be a better value...conjecture sure, but perhaps worth consideration. Cheers,
Spencer