Arafel,
This post will be long and cover a lot of territory, but you've asked a lot of questions!
BUDGET
The Aries + JMW-12 list for about $3,600 right? That's without the .5 arm upgrade ($900), which is essential to handle any decent selection of cartridges. You get a discount, so let's pretend your TT/arm budget is $3500-4000.
TURNTABLE
Chris Brady and Twl both report the 200 series bases outplay the 100 series bases. The biggest jump is from acrylic base to wood, birch to cocobolo is smaller. FWIW, neither of these gentlemen has ever steered me wrong.
There is a similar progression in platter sound. Leaded acrylic beats clear acrylic and leaded cocobolo beats both. CB demoed platters at the Midwest Audio Fair last spring and at VSAC last month. All observers agreed on this progression.
For your budget I'd get a cocobolo Teres 245 ($2575 or $2375 if you sand and finish yourself). This is a killer TT and gives you a clear upgrade path to the 255/265. The only difference between these models is their platters, and CB even offers trade-ins on used platters.
TERES vs. VPI
A Teres 245 will stuff an Aries IMO. This sounds controversial so let's just compare verifiable specs:
- better plinth (cocobolo outplays acrylic, as mentioned above)
- better bearing (viscous damped and tighter tolerances, 12 hour seat time vs. 2)
- higher mass platter (better speed/resonance control)
- better motor (quiet, stable DC vs. noisy, unstable AC; several VPI owners have upgraded to Teres motors; AFAIK no Teres owner has ever changed motors, except to a newer version from Teres)
- better controller (Teres reads platter speed in real time and self adjusts; Aries... umm, I think you fiddle the belt)
- better belt (stable mylar vs. stretchy neoprene means better speed stability, I've tested this on my TT)
You get the picture. I'd expect even a Teres 135 to outplay an Aries, it has every advantage listed above except for the plinth.
TONEARM
More controversy. If you hope some day to upgrade to a Shelter or top Koetsu then you must avoid unipivots. They can't fully control low compliance cartridges and won't let them play their best. The Graham 2.2 is a possible exception, but that would blow your budget.
The OL Encounter is a great arm by all accounts. It is ideal for a Shelter and superb with a wide array of other cartridges. The OL Silver can be modded up to within a whisker of the Encounter, though the Encounter wins in the end due to its superior wire. Read the "Strange Tonearm Tweak" thread for details on modding a Silver and a direct comparison of the two.
Hope all this was helpful.