Was in Lowes today and saw a Porter Cable bench top jointer for $250.00. It had mixed reviews but most everything does. They also have some made by Steel City for about $100.00 more. Don't know anything about Steel City. But it has a Helical Head, and the Porter Cable has the two knife head. Thoughts?
If you intend to build projects larger than scale models or small jewelry boxes then you generally don't want to consider benchtop jointers. Most are powered by universal motors, have small diameter cutterheads, and worse still extremely short infeed and outfeed tables (as a rule of thumb the maximum length board that can be easily jointed is equal to about twice the length of the shortest table).
As for helical or spiral heads, they can be very nice but unless you work with a lot of very highly figured wood (e.g. birdseye, etc.) then it is more a 6-of-one, half-dozen-of-another argument, they have their pros and cons like everything else and you generally are not going to go wrong either way. If I were to choose just one tool to invest towards a helical carbide cutterhead system it would be the thickness planer, first and foremost, as the jointer is only required to provide you with flat and squared surfaces in preparation for thicknessing (a critical role, but not necessarily the finished surface), the real surfacing and final thicknessing happens in the planer where, ideally, you should be removing an equal thickness of material from each side of the board any how (i.e. it will resurface the surface left behind from jointing the board).
As for the helical head on the Steel City benchtop jointer, with just 12 inserts it is likely equivalent to a single knife jointer. My preference is for 3 and 4 knife jointers, two is acceptable, but a single knife can only be made up for by either spinning the cutterhead at ridiculous RPMs (which can greatly increase vibration) or significantly slowing the feed rate, otherwise you end up with a scalloped surfaces. However, its granite beds are fine, as would be cast iron (my preference), but steer clear of those with aluminum beds as they have much less vibration dampening mass and often have inferior grinding quality (they also offer a good deal more friction, hence the reason they are often ribbed).
But, in general, if you are serious about woodworking and intend to build furniture and fixture sized pieces then you really want to stick to 6" or 8" (or larger if needed) freestanding jointers. Benchtop planers, on the other hand, I have no issues with for the hobby woodworker as they have a very simple job to do (i.e. thickness a board after the Jointer has done the real work of flattening and squaring it) -- in fact my benchtop planer is the venerable DeWalt DW735. Stay away from combo jointer-planer machines unless you are willing to pay top dollar for the space saving as anything in the "affordable" realm is pretty much universally junk.
