As an English speaker learning Russian, it is hard to find bi-lingual materials that don't assume knowledge of Russian, the lack of stress marks being the most common offense. This dictionary is almost completely even-handed.
The definitions are reasonably authoritative and the compact plastic binding durable and portable. I found it immensely useful when in Russia. The entries are fastidiously symmetric: I never found an instance where a Russian word was defined but not listed in the corresponding English entry. The Langenscheidt has some gaps in this regard.
It has some shortcomings compared to Langenscheidt. The print is too small to read under less than ideal light; it was impossible to look up something in a car at night. Perfective verbs are not cross-referenced to their imperfective complements. The thick-but-not-broad shape is not as back-pocket friendly as the Langenscheidt.
You must learn Cyrillic. It is *impossible* to represent Russian accurately in the Latin alphabet. If you can't memorize 33 letters then you are beyond anyone's help.
The Langenscheidt is better for my needs, and this dictionary was displaced from my pants pocket by it. But, given the price, I recommend buying both. The Collins is worth carrying around in your bag as a second opinion on definitions and for covering gaps in the Langenscheidt. And as a spare: don't think for a minute you can find a replacement while in Russia.