Based on Kenmore.com product specs and description, we can find that the difference between Kenmore 21514 and 21614 is:
Kenmore 21514 vs 21614
The Kenmore 21514 is white while the 21614 is purple.
21514 uses a standard wand which includes a upper wand and a lower wand, while the 21614 uses a telescopic wand.
The Kenmore 21514 is priced at $229.99 on kenmore.com while the Kenmore 21614 is priced at $269.99 on 2013-04-25.
On the product page, it states that Kenmore 21514 uses Micro Filtration while the 21614 uses HEPA filter type.
If you are looking for a good canister vacuum, you can have a look at this canister vacuum.