Sorry if this is the wrong section to post this in. Not really a comprehensive review, but more of a few random thoughts about the eGo I just received.
I started vaping with a 510 a little over a week ago.
Some observations about the eGo vs the 510:
1. The 510 sits in my shirt pocket nicely, but it could fall out, and I probably wouldn't notice it gone...it's too light.
The eGo is heavier, a lot heavier, but not too big. If it were to fall out, I'd notice immediately. Plus, I can put it in my pants pocket without fear of breaking...it's built like a tank!
2. The 510 won't stand up. It has to be laid down on it's side. It can get lost on my messy desk or table, wherever.
The eGo sits straight up on it's end. Easier to notice amongst clutter and easier to grab. I can set it right next to my various bottles of e-juice, reducing the clutter.
3. The 510 atty gets a little too warm for me when I hit several times too quickly.
The eGo has a cone covering the atty. It hasn't even gotten warm on me yet.
4. The 510 has a pretty good TH & vapor with most of the juice I've tried.
The eGo TH and vapor is easily twice as much and 10x more consistent.
5. When I pickup the 510 to vape, I'm always having to check which end to stick in my mouth. Gets annoying really. I guess I should use colored carts, but I only have had the white ones till now, and my 510 is white.
The eGo is tapered and heavier on the battery end, so I'd have to be very mentally impaired for me to put the battery end in my mouth.
6. The 510 has that dumb LED on the battery end, so I end up looking at it a lot to see if the battery is crankin'.
The eGo has the LED in the switch. Much easier to see what the battery is doing. The LED glows under my thumb or finger.
7. The 510 doesn't fit in my hand like the eGo. I can't hold the 510 firmly in my fingers and still hit the switch. It's too close to the end of the battery.
The eGo's switch is about a 1/2in. farther back, right at the atty end, so my thumb hits it right on target every time.
So, the eGo is superior to the 510 in at least 7 ways to me, make that 8 if you count the battery charge life. No wonder it's so popular!
I'm sold!
However, I'm sure a mod is in my future. 
If you're considering the 510 as your 1st e-cig, I'd seriously advise you to get an eGo from the git-go...if you like.
I started vaping with a 510 a little over a week ago.
Some observations about the eGo vs the 510:
1. The 510 sits in my shirt pocket nicely, but it could fall out, and I probably wouldn't notice it gone...it's too light.
The eGo is heavier, a lot heavier, but not too big. If it were to fall out, I'd notice immediately. Plus, I can put it in my pants pocket without fear of breaking...it's built like a tank!
2. The 510 won't stand up. It has to be laid down on it's side. It can get lost on my messy desk or table, wherever.
The eGo sits straight up on it's end. Easier to notice amongst clutter and easier to grab. I can set it right next to my various bottles of e-juice, reducing the clutter.
3. The 510 atty gets a little too warm for me when I hit several times too quickly.
The eGo has a cone covering the atty. It hasn't even gotten warm on me yet.
4. The 510 has a pretty good TH & vapor with most of the juice I've tried.
The eGo TH and vapor is easily twice as much and 10x more consistent.
5. When I pickup the 510 to vape, I'm always having to check which end to stick in my mouth. Gets annoying really. I guess I should use colored carts, but I only have had the white ones till now, and my 510 is white.
The eGo is tapered and heavier on the battery end, so I'd have to be very mentally impaired for me to put the battery end in my mouth.
6. The 510 has that dumb LED on the battery end, so I end up looking at it a lot to see if the battery is crankin'.
The eGo has the LED in the switch. Much easier to see what the battery is doing. The LED glows under my thumb or finger.
7. The 510 doesn't fit in my hand like the eGo. I can't hold the 510 firmly in my fingers and still hit the switch. It's too close to the end of the battery.
The eGo's switch is about a 1/2in. farther back, right at the atty end, so my thumb hits it right on target every time.
So, the eGo is superior to the 510 in at least 7 ways to me, make that 8 if you count the battery charge life. No wonder it's so popular!
I'm sold!
However, I'm sure a mod is in my future. If you're considering the 510 as your 1st e-cig, I'd seriously advise you to get an eGo from the git-go...if you like.