Don't know if this is expected, but at given URL I see that:
- rendering makes lower text, than shown in your screenshot;
- some rendered letters are not same, as in your screenshot (see in my screenshot for cyrillic sans font second line, second letter - "b"; in serif font see first line, second letter - "B").
- support for arabic isn't worked.
I add attachment with screenshot, where shown how this looks.
Platform: Windows 98, Opera 9.25.
Created attachment 14345 [details]
Created attachment 14346 [details]
Created attachment 14347 [details]
In fonts version 2.24 I found new problems: some cyrillic shapes I see damaged (see screen shots below, damaged shapes are outlined by red line). Damage seen in Opera (see URL for testing page and screenshots), Thunderbird and in alternative character map program (native Win98 charmap doesn't show cyrillic letters).
Also, I again see the differences between shapes in your screenshots on page and rendered shapes, both in sans in serif:
- in Serif second uppercase letter ("B") have longer upper line, than on screenshot.
- in 11th letter ("i with accute"), accute have not same shape, as on screenshot.
- both height and width of rendered fonts are smaller, than on screenshots.
etc. I don't know which side is wrong. Probably, screenshots are outdated (see double dots over lowercase "e" - in screenshots they are shifted right), but in this case screenshots should be updated.
Unfortunately, I can't check shapes in .pdf files from your site - they are hang FoxIt Reader... :(
Created attachment 15037 [details]
Created attachment 15038 [details]
I may add more screenshots and suggestions. I test dejavu fonts (for my native cyrillic) beside Opera also in Thunderbird, and found, that as in Opera  only mono font isn't broken (some shapes in other fonts are damaged and in each font damaged different shapes - I highlight broken shapes in screenshots).
 Mono font also have qurks - its spacing irregular (I mark irregularities in screenshot). Possible suggestion: something wrong with hinting/kerning information.
 Also, I was trying to select fonts for viewing in Opera (Tools / Options / Advanced / Fonts / International), and also found, that different fonts implemented with different quality. For example, Dejavu Sans Ligh implement arabic preview, whereas Dejavu Sans show broken text. Possible suggestion: in Dejavu Sans some shapes have zero-sized shapes hinting, and this makes them invisible.
 The more so, something wrong with missing/present shapes we may found even for international-less shapes. For example, preview in Opera shows, that Dejavu Sans implements all "common punctuation", whereas Sans Mono implements less shapes (even lesser, than Times New Roman).
Created attachment 17160 [details]
Dejavu Sans 2.25 in Thunderbird - some shapes are broken
Created attachment 17161 [details]
Dejavu Serif 2.25 in Thunderbird - some shapes are broken
Created attachment 17162 [details]
Dejavu Sans Mono 2.25 in Thunderbird - spacing irregularities
Created attachment 17163 [details]
Dejavu Sans Light 2.25 - bad arabic preview in Opera font selection
Created attachment 17164 [details]
Dejavu Sans 2.25 - bad arabic preview in Opera font selection
Correction for previous description: Sans Light preview looks correct and shown as sample
Created attachment 17165 [details]
Dejavu Sans and Sans Mono 2.25 - common punctuation preview in Opera font selection, Mono font incomplete
Created attachment 17166 [details]
Dejavu Sans Mono 2.25 and Times New Roman - common punctuation preview in Opera font selection, Mono font less complete