Starting spots in Galaxy.

I actually find it more challenging because I cannot explore in all directions and it is harder during the colony rush unless you get lucky.  But TBH i do like starting 'non' edge beter

I def prefer in the middle. It makes the game more exciting because you encounter more factions/etc.

I know what you mean about the middle being more populated, but one advantage of staying on the edge is being able to establish a large empire and only having to worry about so many fronts. Although it is certainly possible to colonise and dominate the middle, if you start upsetting your neighbors (which I nearly always do) you can find yourself surrounded and having to fight on many fronts. I actually find it easier to start at the edge (I always play spiral as well as it seems more realistic) and build an empire around the edge of map, expanding around the edge of about a quarter or a third of the galaxy. I then move in for the kill once I've established a large enough empire (but not too large as so not to overexert myself) and start to expand into other race's territories by conquering their systems.

However if it is a challenge you are after (from a warlike conquering point of view) then I'd definitely recommend starting in the middle. And if you are the type who likes to make friends and be pacifistic then again being in the middle is a good bet.

I find an edge start is more challenging to my colony rush expansion strategy.  I can only expand in half the directions I have available in a mid-galactic start.  Because I also delay developing my military, being in the middle means more factions declare war on me for being weak.  Then again, being on the edge usually means I have to fight my way out to discover the rest of the galaxy.  So, the challenges are different enough I can't say I have a clear preference.  Being on the edge and fighting a war on the opposite side of a very large map can get tedious, and that is the main difference for me.

Being on the edge always means I'm weaker because I have fewer/less powerful planets. The middle usually offers more juicy ones. Both can have their challenges so I don't mind.

I find the edge has a better early game because it ismsafer, but a worse late game because shipyard decay and long travel times and lost influence spread. By influence what I mean is that from the middle your influence goes in all directions each turn. From the edge it only goes toward the center and some is "wasted" by going off the edge of the map.

If you make it to late game in the middle, game is over way too easy with an influence win. From the edge an influence win takes forever.

Ah that's probably why I haven't noticed this, I only ever play with Conquest victory and Alliance victory settings turned on. 

I usually don't use any victory conditions. At some point I realize the ai players are so far behind that I can win whenever I want, it is just facing the multi hundred turn slog to get to the victory screen is tiresome, so I start a new game.

Influence though, is so powerful from the middle of the map that now I only play from the edge. Otherwise I have all the ai players choked off and isolated too fast.

Also remember being in the middle gives you a practical scanner and speed buff. If going from the middle to the edge is 100 tiles then going from edge to edge is 201 tiles. You need twice the scanning and speed to attack your farthest enemy from the edge. This means slower response times with ships built at your core planets. If you have an insane 70-speed warship, from a shipyard in the middle it can attack over 75% of the map on the same turn it is built, And it can hit any tile on turn 2. If the same ship is built on the outer rim less than 40% of the map is in range on turn 1 and some of the map can't be hit at all until turn 3. In late game wars these factors give the middle a huge advantage.

So the real trick is knowing if you enjoy a challenge early go middle. If you enjoy a challenge late go edge.

I like to specialize an empire the have to win using what they are worse at along with not touching the economic wheel or slider, not knowing the tech tree and starting on a side.

In short make things as difficult as possible for yourself.

You should try MacSen's faction, "Terran Resurgence", -2 on all faction abilities.  It is insanely masochistic.

There is also the home system that has no habitable planet at all.

I much prefer starting from the edge. Already got enough annoying disruptions for one front, i don't need to be surrounded by them!