[TenTec] How to Choose an SDR RX for the Pan-Adapter?

[Rick - DJ0IP / NJ0IP]

This topic in similar form has been covered in many different threads here
and in the other TT groups.

I want to add an external pan-adaptor to my older Eagle.  My Eagle has no 9
MHz out and also has no TMP jack on the filter board for tapping into the
IF.

WHAT I AM LOOKING FOR:
'Specific information' about how to compare the technology of the various
receiver candidates.

WHAT I AM 'NOT' LOOKING FOR:
Comments like: "I've had good luck with XYZ".  
Besides being an almost useless comment, we've read those types of comments
multiple times already.

BACKGROUND:  
Although my Eagle has no easy provision for 9 MHz out, it does have the
2-jack mod which routes the transmitting antenna out the back panel, AFTER
the signals have passed through the Eagles RX BPF's.  I suppose this
eliminates the need for BPFs in the External RX, but it is probably better
to have them anyway, so that I can also use the RX as a stand-alone.

My personal interests stop at 30 MHz, but in the interest of completeness
and learning, if there are benefits in the various technologies above that,
say up to 70cm, then please share them with us too.

It will be FAR EASIER for me to simply use the ANT OUT line on my Eagle than
trying to tap into the 9 MHz.
I'm not afraid of using a soldering iron, but the Eagle is very tiny and my
eyesight is very poor.
Unless there are some darn good arguments for an IF connection, I will use
the ANT OUT.

THE BIG QUESTION IS:  JUST HOW GOOD DOES THE EXT RX NEED TO BE?
Remember, I wish to do this on a shoestring budget, but maximize my bangs
for the buck.

I have read suggestions for:

* Softrock Ensemble III
* FiFi  (a German RX costing abt. $165 in kit form)
* SDR-4 (an English RX costing abt. $300)
* LP-Pan
* Fun Cube
* Watson W-SDRX1 (my own suggestion; is also available locally under another
name for $110)

IN SUMMARY:
How do I compare and evaluate these candidates?
I am interested in things like on-board technology, and ease of
implementation.

I wish to keep it simple and I have zero interest in installing Ham Radio
Deluxe or any similar over-kill product.
I do have N4PY control software for my Eagle.
Though I'm looking for a cheap solution, I am not looking for the cheapest
solution.  If I can get advantages for spending an extra $50, then I would
probably do that.

Thanks in advance for technical information on this topic.

73 - Rick, DJ0IP
(Nr. Frankfurt am Main)