What should you spend more on product development or marketing? and why?

Hai Md. 
Both are two different segments, altogether. 
As such, relative or rational comparison is not possible. 
I will give a simple case study:  In India, "ALPENLIEBE" is very famous among kids. 
The main reason is ADVERTISEMENT. 
The manufacturer spares no expenses in getting extraordinary mileage for this product. 
The cost of the product is just50 paise per unit.
  In this case study, marketing expenses is VERY HUGE compared with the product development cost. 
There are several such products in this category alone. 
My CONCLUSION, therefore, is both product development expenses and marketing expenses are totally INDEPENDENT of each other, but, the expected end-result is ALWAYS the SAME.
  PROFIT MAXIMIZATION!!!  

Spend money on Product R&D With social media and changing in IT technology there are various platforms to market your product in a cost effective way Clever marketing and slogans

If the product is being developed based on consumer driven prospectives, it will need the least markting efforts to hit the lists

Awareness program is the best thing.
First of all just make people to understand your product qualities.
By DEMOS.

Product development without doubts.
This way you will make it longer lasting and more competitive against competitors.
It's true one of the four P's of Marketing is Product but usually this is not part of the Marketing Manager but of an engineer, etc.

I guess that , both are important equally , but if I should choose .
Marketing is the face and development is the inside and the face is more important to gain better market

Dear Mahmoud, Hope you are fine and doing well.
Product Development and Marketing, though are completely different fields, are linked together in certain aspects.
Product Development has overall contribution to the business to generate better products, which in turn provides the building force for marketing to talk about when presenting and promoting the brand and its product range as a superior product in the market.
This is especially true for B2B formats in industrial manufacturing where product sales are driven by technical superiority of the product as advertised through marketing, and will be less relevant in retail shopping formats where products are standardized and sales are driven more through promotions and discounts at retail outlets.
Marketing budget allocation should always be defined and is typically a percentage of the projected sales for the year, because marketing still has to sell existing products whether new development happens or not.
Thus, marketing spend may not be compared to product development as the role played by both is different.
The allocation for marketing may be more if the brand is entering new areas or is not known in the market or has stiff competition, and will be less if the brand is established and only needs to refresh its presence with customers.
Product Development on the other hand, has bigger implications.
If it is a technological field like mobile communications or IT, re-investment of upto30% revenues into R&D and product development may be necessary to keep the product technologically alive and going in the market.
Thus, spend on product development should be in line with the technological sensitivity of your products in specific and the investment policy of your company in general.
Hope this helps to set the investment levels for marketing and product development.
Regards, Sanjay Dukle.

تطوير المنتوج يحدث وفق دراسة متطلبات المستهلك و احتياجته فمن المهم أن يصل المنتوج الى أكبر عدد ممكن من الحرفاء و هذا يتوقف على وضعية المنتوج في السوق : - اذا كان المنتوج تم طرحه حديثا بالأسواق يجب في مرحلة أولى التسويق له حتى يصل الى أكبر شريحة ممكنة من المستهلكين وهنا و جب التركيز و العمل على تسويق المنتوج و التعريف بيه .
- لكي يحافظ المنتوج على مكانته في سوق المبيعات يجب ان يواكب في مرحلة ثانية تطورات السوق وما يحدث فيها من تغيرات :استهلاكية و تكنولوجية...
تسويق المنتوج و تطويره هما عاملان متكاملان واساسيان تتوقف اهمية كليهما بالنسبة للاخر حسب وضع المنتوج بالسوق.

Hi, Everybody agrees that the consumer awareness has increased multiple fold over the last decade,even in emerging economies.
With plethora of information available to the customers at their fingertips,it is virtually impossible to escape their sight.
Now coming to the question-I think that product development is a skill/outcome of R&D in accordance to the vision of the organisation.
Now the marketing of the product will depend on the kind of Product Development that has happened.
If there is a breakthrough in technology,process which has completely changed the dimensions of the industry,the marketing expenses would tend to be low.However if the changes are merely 'Gimmicky' in nature then the explanation of the nuances would require a lot of expenditure in marketing.
According to me the expenditure in Product Development and Marketing varies from Industry to industry.
Whereas Pharmaceutical companies would spend more on Product development in comparison to marketing,the FMCG companies would tend to spend heavily on marketing and less on Product Development in the long run.
To conclude-In my opinion it is very important to keep churning new and innovative products in sync with the future growth,it is equally important to reap the benefits of a Product by alloting adequate marketing budget.
Although the product development/marketing budget ratio varies across industry,in the longer run the companies who really excel tend to have it split60-40 in favor of product Development.

we need to focus on both at the same time, if we focus on product development while neglecting the marketing side, the product is not going to be a success and it will not be at the head of the list.
as well, if we focus on the marketing side, the product fails at the other competitors and will be exceeded in the eyes of consumers.
  in my opinion, the marketing efforts rubs shoulders effort developpemnt for satisfactory and lasting results.

Hi Mahmoud, This is kinda integrated thing,you cannot market what you don;t have,product development is part of the product marketing process,about the spending & budgeting i think it depends on the product type,product lifetime,Segment you are offering (B2B or B2C).
Ahmed