Invert Mini if you don't play alot (to save money)
Proto Reflex Rail 2011 if you play alot (the cost of the gun will repay it's self)
Invert Mini - 20 BPS max
Pros: Cheaper, EASY maintainence, Tiny, Works great Imo, and it has no Macrolines
Cons: i think the trigger isn't that great its too 'wiggly' nuff said, Theres no On/Off ASA, and i kinda hate the feed neck because my Invert Mini didnt come with the allen key to tighten it. Out of the box it is not very efficient untill you break it in with 20 cases of paint or so (or buy a Bolt + Spring kit and then tune it), and i hate the feel of the front grip; its nice and tight at first but i realized i can't grip my fingers comfortably around it.
Conclusion on the mini: Once you get it i suggest an On and off ASA (which is $80 from Empire...) a new trigger ($30 to 50), and even with the new trigger (i didn't want to pay $80 for the Asa) i thought it was a decent gun, 7.5/10
Proto Reflex Rail 2011 - 25 Bps max (Bps doesnt really matter to me since i leave my guns at 12.5 bps but i'm just throwing that out there for you to consider)
I Dont have one of these but everyone who has one (and some people upgraded to this after buying an Invert Mini) is really happy with it, I myself was considering upgrading to this or buy my brother's Etek 3, but i have had a chance to get my hands on it (and played three games with it) and here are some details that i can give you.
Pros: I liked the Front grip alot more then the Invert Mini's because i can wrap my hand around it and get a better feel, Next the Trigger is beautiful imo because it sticks out further (its much more comfortable for me to walk with the trigger further out) and it doesn't wiggle like the Invert Mini's trigger along side that the trigger gives a more Crisp pull to it that I find pleasing, the Ergonomics of the Proto Reflex Rail trigger grip is amazing i love how it slants a little bit unlike the invert mini (for more comfort, but some people don't like this)
And it has an On/Off Asa with it (HUUUGGE bonus in my book), Lastly the Eye pipe just makes cleaning it alot easier
Cons: I heard that some people said that the support/warranty center for Dye and Proto were a hassle (but i personally don't know), Price (i just think $500 is a lot in this type of economy)
OVERALL Conclusion: I probably going to save up for a Proto Reflex Rail '11 in the future, and keep the i have Invert Mini as a Backup gun), All the upgrades for the invert Mini (I.E. The Trigger + Asa + Bolt and Spring kit) still don't make it as good as the P.R.R 11 imo (i've got to try out all the upgrades on someone else's gun, it makes it more efficient but for the price of the Mini + the Upgrades you could have gotten something nicer). So i suggest going with Proto Reflex rail if you play alot.
In the longer run i like the Proto Reflex Rail much better then the Invert Mini (the Proto Reflex Rail is great for stock i give it a 8.5/10 because i didn't have a chance to play a FULL day with it and i don't know what the maintenance is like) as for the Invert mini's 7/10 (stock), and maybe 8/10 with all the upgrades). I think also that the Proto Reflex Rail is much more aesthetically pleasing.
I'll see if i can get one of my friends later to fill you in with more details on the Proto Reflex rail regarding to their experiences and maintaining the gun.
I hope this helps you! ^_^