DS fits in pocket easily, Neil doesn't
At under 10kg the DS is lightweight to carry, at over 10kg Neil isn't.
Neil is considerably higher resolution, plus in 3D without needing extra screens or equipment. Colour rendition is also superb.
Neil provides 3D directional soundscapes of highest fidelity including thundering bass, DS is regular stereo but does come with headphone socket.
Both devices provided limited networking capabilities though both are wireless out of the box. The DS is limited to early wifi protocols with poor security though Neil is adaptive and can use current networking standards and most protocols.
The DS comes with two expansion slots. While one is used for the game cartridge that leaves only one possible for expansion options (GBA cartridges or custom game controllers for example). Neil on the other hand can expand considerably if required without need for dedicated ports.
Easy and comfortable to hold with one hand though gloss plastic surface can make it slide out of a pocket easily. Operation requires use of two hands however leaving one armed cripples like me unable to enjoy to the fullest. Neil can be operated with one hand is needed and even no handed via built in voice operated capabilities.
The DS is well designed and compact with needless ugly external protuberances. Third party options in the form of stickers can be used to personalise your DS without voiding warranty or impeding function. Neil is designed on the generally accepted male platform. Build quality is functional with no silly finshes such as teak or carbon fiber. Neil also comes with third party options for personalisation. Both piercings and tattoos though are considered permanent and as such will void warranty. Piercings may inhibit or enhance performance and as such not a DIY personalisation, qualified installers are essential. An infinite array of external coverings are available for the Neil for decoration and protection.
Neil: 90 (-10 for aesthetics)
The DS performs well for its games, with little to no visual artifacts gameplay is consistently smooth. Neil performs fast at commonly used tasks but performance can be inconsistent with internal and external factors possibly impacting it. A good feature of the Neil is the adaptive learning allows performance to improve on task repetition.
The DS was competitively priced at release date (unknown) and is available on the second hand market even cheaper if you look. Neil was cheap to manufacture but ongoing costs to bring it to its current configuration were considerable. Given further ongoing costs are needed to keep Neil operational and no known models are available on the second hand market its hard to compare cost effectiveness. Though on straight dollar costs the Neil seems to many a poor choice but the right owner will find Neil exceptional value for money.
Neil: 0*(see comment)
DS peforms for several hours before shutting down requiring a few more hours of dedicated charging before ready again. Neil has a charging downtime cycle though is able to operate at any instant. Performance may suffer if overused and food/bed for recharging unavailable. Operator care is required to not overstress Neil and withhold downtime.
The DS is able to entertain using a wide variety of games which are widely available for the platform. Its battery life may be an issue on long journeys or destinations without electricity. Ditto the Neil. Neil is self mobile so luggage space to stow it is negated.
A surprising result considering obvious bias towards electronic gadgets. Neils autonomous and learning capabilities really edged him ahead in this comparison.