(Disclaimer: This page is intended for people wanting to use their strobes mainly for sports and/or the occasional location portrait work.   This is not intended for those who are looking for a solely studio system.)

Buying the right set of strobes is like buying a car.   You need to figure out WHAT you are going to use it for, think about HOW you're going to use them and WHERE they are going to be.   Also, chances are it's going to cost you about the same as a car.   You don't buy a Ford Focus to tow your speedboat just as you don't buy a Dodge RAM because you like how nibble it is and it's ease of parallel parking.  

If you like getting something that handles everything you throw at it, you do what I did, get a V6 Jetta with the sport suspension and slap a Stage 2 turbo system in it.   It gets my groceries, it takes 90-degree right turns at 40 MPH without drifting or under steer and it has 425 ponies under the hood for when I need the speed.   Speed, adaptability and ruggedness are what I as looking for in my lighting system.

MONOBLOCKS OR PACKS:
Oddly enough, this seems to be the most lopsided argument for all the wrong reasons.   A monoblock (more commonly referred to as a uni-head) has everything encased in one nice little package.   The only cords you need are a power cord and a sync cord.   They are compact allowing you to easily ship them from venue to venue with ease.    The power pack and head system on the other hand is a little more bulky and you need about 50% more shipping space to get them from point to point.   They are also generally more expensive -- and as we all know photographers are a rather cheap lot -- which is why you'll see so many photographers advocating the monoblocks; simplicity and price.   What they fail to take in to consideration are the technical differences between the two systems and some of the functionality differences that can come back to bite.  

WHICH IS EASIER?
This totally depends on how you'll be using them.   I do a lot of location work where my heads are on booms and often on fully extended 13 foot light stands.   If I need to make an exposure adjustment with a monoblock, I need to lower and raise the stand each time.   That takes time and slows down the entire shoot.   With a pack system, I just reach over and flip a switch.   If you never plan to use the lights more than 8 feet off the ground then this isn't an issue.   For me it's every time I light something.

The other problem is a safety concern.   The X3200 weighs in at 7.1 lbs.; the 4080sp head (dynalite's heaviest) is just 3.4 lbs.   If the stand should tip over, the monoblock is going to do more damage to whatever it hits and especially to the unit itself.   There are more parts inside the X3200 that are likely to break in the impact requiring it to be sent in for repair.   Now you're essentially short a pack and head instead of just a head during the repair process.

POWER AND DURATION:
In terms of raw power, you can't beat power packs.   White Lightning's most powerful monoblock, the X3200 only puts out 1320 effective Watt-Seconds (Ws) at full power for 1/900 th duration.   On the other hand, with a bi-tube Dynalite 4080sp head you can use an M2000 power pack and get 2000 true Ws at 1/2600th duration.   (That's an illogical interpretation based on the Dynalite website which would suggest 1/1500th.   The math is more complicated.   On the phone they'll state full power yields 1/2600th duration with a bi-tube head.   Call up there offices at 800.722.6638 for your own verification.)   Another nice thing about the 4080sp is that you can use two power packs on one head for a maximum of 4000 true Ws.

If you are intending to light an arena, it is CRUCIAL that your strobes can over power the ambient light by at least 4 stops.   Some cameras with the CMOS sensor are more sensitive to light and 5 stops is recommended.   The reason is simple; if at maximum power your lights are only 1 or 2 stops over ambient, you'll still have the ambient light effecting the photo.   With a camera that can sync at 1/500th this isn't to horrible, but with a sync of 1/250th, it will drastically effect the quality of your images.

We all know that a shutter speed of 1/500th is not fast enough to stop action.   It's a misnomer.   To totally freeze the action you need to be shooting above 1/1250th in my opinion.   This obviously is not possible indoors due to flash sync issues.   Instead, your flash duration becomes your shutter speed.   If the strobes are only on for 1/1500th of a second that essentially is what your shutter speed is.   Full power on an X3200 is 1/900th.   Presuming you have the flash 5 stops over ambient; you're still going to get motion blur in the fingers, feet, ends of hockey sticks and on the basketball net.   

INTERNAL WIRING:  
You'll often not need to use your strobes at full power and can comfortably get away with powering them down a bit.   Depending on the specific make (and model year if you are buying used) this might not be a good idea.   In most cases like with the Dynalite's and White Lightning's, as you power the strobes down you will shorten the duration.   The Dynalite 2000 watt packs with the aforementioned head have a duration of 1/2600th at 2000W, 1/3800th at 1000W and 1/4500th at 500W.   It is important that in order to get those figures you need to use the output toggle switches INSTEAD of the 1/3 stop variator dial.

Some systems on the other hand achieve their shortest duration at their maximum power settings.   Dialing back will actually lengthen out your duration at an inversely proportionate rate as the figures listed above.   This used to be rather cut and dry but in recent years, manufacturers have made some modifications to the internal wiring of their units.   If you have to buy used, do your homework and call the manufacturer.

So in 1000 words or less those are some of the pro's and con's to both systems.

BRANDS:  
White Lightning has great units but they don't offer the power nor flexibility I desire.  

Elinchrom has amazing units but at the time when I bought a system they weren't rugged enough for extensive shipping.  

Alienbee I continually preach against do to major performance issues for the environment many people try to use them in.   They can light a high school gym, but do not expect even moderate quality gains in a 3000 seat or larger venue unless the lights are turned off.  

Profoto is my dream kit but they do offer much in the realm of light modifiers for sports and they are astronomically more expensive.  

Dynalite fit my needs to a T.   They are priced on the higher side but they are built like tanks and offer exceptional flash duration and recycle times.

Speedotron is the light of choice with Sports Illustrated and most arenas with permanent, rentable systems.   They are typically quad-tube heads with a power pack suited for the arena's lighting needs.   They're awesome, but they are heavy, expensive and tend to be meant for permanent installations.