Combining 3x Barlow + 10mm eyepiece is superior to a 4 mm eyepiece

This triple-magnifying, very well made Barlow also fits the Sky-Watcher Heritage 76 Mini Dobsonian Telescope. This beginner's telescope with 76 mm diameter mirror and a focal length of 300 mm, which reaches with its eyepieces 25 and 10 mm, a 12- and 30-fold magnification, comes along with the Barlow lens that is inserted in front of the eyepiece, on 36- or 90-fold total magnification. As expected, the field of view and image brightness have become smaller.

One might be a bit easier to handle alternative would be a 4 mm eyepiece as Orbinar Plössl 4mm telescope eyepiece 1.25 "(31.7mm) 4-lens, which provides a magnification of 300/4 = 75.

Addendum dated 07.30.13: With a further observation of the planet Saturn in somewhat poorer visibility conditions the combination yielded from 10 mm eyepiece, the Barlow lens which noticeably better picture. Not unimportant is that one the focus easily manage than the 4 mm eyepiece.