i dont want to come off as picky or miss know it all
but you asked for honest opinion and here's what i think
$45 dollars is a fair price especially if it included shipping
but personally i am very critical and picky when it comes to drawings
i was raised by my grandparents whom are crazy artists/professors. they are the kind of artists you would call the traditional institutionalized kind and hates "deviant" art or artists (like dada artists).
i am a "failure" by their standards
so basically here's what they would say if those drawings came from me:
"the pencil one lacks contrast. there's no depth. its just floating on the paper. too many light parts with not enough darkness to contrast. the hairs are too stiff and lacks life. the eyes does not shine nor do they capture the observer's eyes. the coloured one feels a little lost. the jacket has nice contrast and colours with the correct shades but the hair has no contrast at all. theres such a lack of contrast on the dog's face that one would not be able to tell if the dog has a muzzle or not."
but if it was up to me to buy one of those two pictures i'd take the coloured one. its much easier to draw black and white - and a lot less work and planning, if theres a mistake the eraser will fix it but its a lot harder to fix coloured drawings. i love colour in general and i think doggie drawings should always be in colour. what other way can you reflect their colourful personality