The Line 6 Spider IV 150 has to be one of the best values in guitar amplifiers today and could be a 5 star amp if it holds up. The amp is powerful and produces high volume clean sounds with its 2 12 inch Celestion custom speakers. I do not have detailed specs on the speakers so I do have some concern about their longevity given the relatively low total price of the amp. The volume is more than enough to set your ears on overdrive and to compete with the loudest of drummers with power in reserve. Any desired distortion really comes from the multitude of FX selections and not by overdriving the amp. To many purists who think that overdriving tube amps is the only proper way to get the sound they want may be disappointed in this solid state amp, but I believe even those purists will find the ability of this amp to come close to producing the sound they desire by choosing one of the many, many built-in FX and tweaking it if necessary by editing capabilities contained within the amp. I will not go into the hundreds of sound presets because they are enumerated within the sales literature here on the Sweetwater site or on the Line 6 website which contains many samples for you to hear. I conservatively will just say there are many, many sounds and they are mostly very, very good. I would also like to point out the efficiency by which sounds are chosen and edited with the rather limited number of knobs, switches and cursor controls on the face of the amp. The relatively few controls may deceptively lead one to think that the simplification means reduced variety and flexibility. This is far from correct considering the vast flexibility of sounds that this amp can produce. These controls are easy to use with very little learning curve regarding the use of the systems and menus. One professional caution: The number of presets may lead to false satisfaction and reduce the amount of your editing and experimenting because you may easily be overcome with the number of presets available. When you find a preset that is close, you will be tempted to accept it. Please take it a step or two further beyond mere acceptability by editing it to make it your perfect sound. It is just too easy to accept what the amp gives you instead of you telling the amp what it needs to give you.
In my opinion, these presets or your personally edited versions of them will permit the disconnection of many of the floor boxes and pedals which many guitartists use today. The problem here is that foot controls are absent from the Spider IVs unless you spend extra money on one of the elaborate foot boards that Line 6 sells to go with the amp. When I bought my Spider IV 150, I also needed to buy a Line 6 footboard to go with it to take full advantage of its amazing capabilities. (I previously had been using a Korg Toneworks AX1500G and a little Korg Pandora PX5D. These are/were fine multifunction units but were add-ons and not integrated with the Line 6 amps.) In my case I chose the FBV MkII "Shortboard". It has 13 lighted switches, an expression pedal and a lighted display panel. There is a more elaborate board with 2 pedals and more switches. This board seemed a bit too much for me, but it would certainly be at home with a "Spider" amp because you would need eight legs to operate it. There is also an express board with 4 switches and a pedal which seemed insufficient for the Spider IV 150 amps functions. Generally, the shortboard addition increases the discounted price of the amp by 40%, but I believe this board is necessary for the amp to be a complete piece of equipment. The shortboard is also the vehicle by which updated software and additional sounds and FX may be downloaded from the Line 6 website into the amp. The shortboard itself is built of high quality, heavy duty materials which seem like they will last longer than you. The steel footswitches feel great and do not have the spring loaded clicker that makes a noise each time you step on the switch. The display is bright and large enough to easily read while standing. I am no expert in foot controllers, but this one says quality as soon as you remove it from the box. While not being excited about spending the additional money for the board, it is still probably a lot less than the large investment in various foot controllers that may be necessary for some guitarists. But, it integrates so well with the amp, it is difficult to refuse to add it. Accordingly, I think it is most beneficial to include something about the boards in any review of the amp. If you already have a large investment in FX foot controls, you do not have to have the Line 6 board, but I would try to remember to consider it as a possibility if you are in the market for one or two additional FX foot controls later on.
Is the Spider IV 150 still a great value after spending the additional money for the "shortboard"? I still have to say absolutely, because the value added by the shortboard is significant and it makes a great amp become a great package. While I highly recommend the Spider IV 150, that is a personal opinion and obviously, you should only make a purchase decision after trying one out. I think most will be pleasantly surprised. While I think this amp is a great value, if it is on the high side of your budget, I think the several less powerful versions might make a great deal as well.