Jim Roseberry
As with mics, there's an overwhelming number of pre-amp choices.
Try to narrow the focus by defining the "character" (or lack thereof) you're wanting from the pre-amp.
 
The Solo 610 has a warm/soft character.
It's not particularly aggressive sounding.
I had one for years... but (for this reason) it was rarely used.
Neve preamps (and clones) always sounded "better" (more aggressive) to my ears.
In particular, there's an articulation on transients that my other pre-amps lacked.
Everyone's aesthetic taste is different.  The Solo 610 may be exactly what you're looking for.

Thanks jim, I don't have any high end mic's meaning in the same price range or higher as these pre's but I am hoping to pull the better out of the mic's I have with a good front end. These are the mic's I have right now. I will at some point invest in a higher end mic for sure.
Rode NT1A, Octava 319, MXLv67, MXL V63M, AT4040, MXLR40 Ribbon and a couple of Sure 57's and 58's.
As far as a mic pre's go, I tend to record more ballad or rock ballad type music than screeming guitar and vocals stuff so wondering if a softer sounding pre is more suited for me. I guess that's why Markhaskin asked what type of music I record. Makes sense.
So for mellower music a more softer saturated sounding pre is better?
For more harder music a cleaner higher volume pre is better?
This kind info may steer me in the right directing.
I need more iinput Johnny Five..

Soft/thick (perhaps a tad dark) is how I'd describe the Solo 610.
 
You can get lost in the aesthetics of mic pre-amps.  
One of the best combinations I've ever used is a C24 (stereo C12) through GML mic preamps.
This was at a studio in Nashville.  Full, a little dark, super detailed, and super quiet
Of course, this combination is out of most budgets (including mine).
 
I'd try to have a listen to the following:

• Solo-610
• Focusrite ISA
• Neve (or clones)
• API (or clones)
• Avalon 737 (especially if you were looking for external Comp and EQ)
• LA-610 (which combines the 610 pre-amp with an LA-2A smooth style compressor)

 
That would give you a good idea of where you fall taste/sound wise.

Mosvalve...
I need more input Johnny Five...

both of those are excellent choices.
 
have you considered any 500 series preamps?
 

batsbrew
both of those are excellent choices.
 
have you considered any 500 series preamps?
 

I'd like to check them out. Can you provide a link?
 Are the 500 series modules?

http://proaudiotoys.com/advanced_search_result.php?x=0&y=0&keywords=500+
http://www.soundpure.com/search/500
 
These are some 500 series examples. Basically, you buy a box that handles some number of 500 series items then you buy the items. The box can be like $500 and the modules tend to be between a couple of hundred and 1000.
 
This holds 2 500 series cards.
http://proaudiotoys.com/bae-dlb-dualchannel-desktop-500-series-lunchbox-w-1x-312a-p-865.html
 
This holds 6 cards
http://www.sweetwater.com/store/detail/API5006B-DB
 
This one holds 8 cards (I think it doesn't come with the power supply)
http://www.soundpure.com/p/api-audio-500-8b-8-slot-500-series-lunchbox/8642
 
This is a pretty similar idea to https://seventhcircleaudio.com/ idea. The difference is that you can save some money by doing some soldering yourself with the seventh circle approach.
 
Really, if you are going to get 8 nice Pres in a 2U space, you're going to spend a chunk of change.
 
Both are modular and can grow.
 
The 500 series items have been criticized by some, but they are pretty interchangeable and practical.
 
Both allow you to grow over years. Like 1 Preamp a year for 8 years? Makes sense to me.
 
How cool to say you've made them yourself. That just gets you loads of cred!

gswitz
http://proaudiotoys.com/advanced_search_result.php?x=0&y=0&keywords=500+
http://www.soundpure.com/search/500
 
These are some 500 series examples. Basically, you buy a box that handles some number of 500 series items then you buy the items. The box can be like $500 and the modules tend to be between a couple of hundred and 1000.
 
This holds 2 500 series cards.
http://proaudiotoys.com/bae-dlb-dualchannel-desktop-500-series-lunchbox-w-1x-312a-p-865.html
 
This holds 6 cards
http://www.sweetwater.com/store/detail/API5006B-DB
 
This one holds 8 cards (I think it doesn't come with the power supply)
http://www.soundpure.com/p/api-audio-500-8b-8-slot-500-series-lunchbox/8642
 
This is a pretty similar idea to https://seventhcircleaudio.com/ idea. The difference is that you can save some money by doing some soldering yourself with the seventh circle approach.
 
Really, if you are going to get 8 nice Pres in a 2U space, you're going to spend a chunk of change.
 
Both are modular and can grow.
 
The 500 series items have been criticized by some, but they are pretty interchangeable and practical.
 
Both allow you to grow over years. Like 1 Preamp a year for 8 years? Makes sense to me.
 
How cool to say you've made them yourself. That just gets you loads of cred!

The 500 series and the seventhcircleaudio stuff looks like it's the smart way to go if you do this for a living.
 
I'm thinking my Saffire Pro 24 has a couple of clean pre's. I also have the Presonus D8 which I think sounds different than the Saffire so something like the 610 will give me something different than those two thus having more options. Am I correct that the 610 is much different than the D8 and Saffire pre's?
 
Choosing a pre amp is not as easy as I thought it would be.
 
 

Mosvalve
The 500 series and the seventhcircleaudio stuff looks like it's the smart way to go if you do this for a living.

I don't make a living doing it, but it has been a long time hobby. The most expensive stuff is anything that becomes obsolete.

these modules:
http://www.adesignsaudio..m/500-series-mic-pre.htm

this for a large chassis:
http://www.sweetwater.com/store/detail/SixPack
this for singles:
http://www.sweetwater.com/store/detail/CPS501

Hi. I can vouch for the LA 610. It ads color. But i love mine, and will never consider selling it. If you have clean preamp (s), the Solo or LA 610 would definetively add another flavour to the table.
It all comes down to budget and personal taste.
I think you will be good to go whichever you choose.
Best of luck,