DNG size

DNG raw can be two types: "mosaic" and "linear". The mosaic DNG is a common raw as is. The linear DNG means that color interpolation already processed by the DNG converter. It's suitable, for instance, for raw converters which don't understand a non-standard color pattern.

Adobe DNG Converter has several parameters for conversion responsible for compatibility with other programs. They can be set at once as preset, for instance "Camera Raw 7.1 or higher compatible". Or can be set explicitly: version of DNG specification (1.4, 1.3 or 1.1), linear or mosaic,  compressed or without compression. Let's see how this parameters changes the size of the DNG file.

Mode\Photoextreme ISO 200  ISO 6400
RAF size 25 MB 25 25
Camera Raw 2.4 48  54  54 
Camera Raw 4.1  48  54  54 
Camera Raw 4.6  48  54  54 
Camera Raw 5.4  48  54  54 
Camera Raw 6.6  48  54  54 
Camera Raw 7.1  16  20  18 
mosaic, compressed  16  20  18 
mosaic, non-compressed  32  32  32 
linear, compressed  48  54  54 
linear, non-compressed  94  94  94 

As you can see Adobe DNG Converter creates mosaic DNG only in the mode "Camera Raw 7.1 or higher compatible" and linear DNG with roughly 3 times more size for the other compatibility modes.

Compatibility with tested converters

 mosaic  linearRAF

Adobe Photoshop Lightroom ver. 4.3

(results exactly the same)

 yes  yes yes 

Raw File Converter EX powered by Silkypix

ver. 3.2.13.0

don't see don't see  yes

Silkypix Developer Studio

Pro ver. 5.0.32.0 

reject  yes  yes 

Capture One Pro ver. 7.0.2 

yes, but without the profile of X-E1 don't see  yes 

DxO Optics Pro ver. 8.1.2 

don't see  don't see  reject

ACDSee Pro ver. 6.1 

broken jpeg (wrong colors)  yes  reject 

Dcraw ver. 9.17 

broken jpeg (wrong colors)  yes  yes 

Raw Therapee ver. 4.0.9.50 

broken jpeg (wrong colors)  yes  crash

As  you can see the proprietary RAF format much better supported, than open standard DNG. Thus don't use DNG if you don't need it.

Examples

ACDSee Pro + mosaic DNG ACDSee Pro + linear DNG
dcraw -a + mosaic DNG dcraw -a + linear DNG
Raw Therapee + mosaic DNG Raw Therapee + linear DNG
Captire One + mosaic DNG Capture One + RAF (for comparison)

As you can see sometimes DNG can be useful. For instance, if you prefer ACDSee Pro or free Raw Therapee.

Conclusion

Only Capture One shows accurate result comparable to the camera jpeg. And it has the promising auto correction tool. Also I was surprised by power of Dcraw, but this program is inconvenient for serious work.