IMO the mini is a downgrade in terms of ergonomics from the Axe. I hated the mini but I somewhat liked shooting an axe for giggles. Still not my cup of tea when it comes to electros. Generally most people dislike the mini, but love the axe. Sometimes it's the other way. Your mileage will vary on this one.
Dangerous power G5-
I've messed with the DP FX, can't say much about the g5.
Etek 4 LT-
Newer than what I have messed with (Etek 3, Ego10, Ego11 if you include dicking around). I enjoyed shooting my Etek 3 LT, very simple to maintain, solid workhorse, and you literally air/chrono/paint and go. Now if you want to have the LCD and and all the whistles, then that's another story. I enjoy turning off my brain and focus on paintball instead of having to deal with my marker and the 30000000+ functions.
Currently own one. I really like it. It shoots very well and I love that it's a single tube instead of the double tube setups that I've been used to. The maintenance is pretty straightforward, unless you're me and you grease the bolt guide, which in turn causes bolt stick (go figure...).
We talking newer or older ones? They shoot like a spoolie should and performs like the pricing point. I had an 08 and it was meh. Nothing really to write home about.
Out of everything, I would go with the Etek 4 if you're a dedicated poppit shooter.
I do however recommend you to look at older high/midends if you don't mind going the used route.
There are tons of markers out there and the used market is so flooded, you can snag some great deals if you bide your time.
Somethings to look at at the Sub $500 range in no order.
Macdev Cyborg RX
NXT Shocker with a ton of upgrades
Boblong Marq/Rapper/Whatever the lineage naming scheme goes